here is a page with working cams on S8 exynos (Europe I guess). I don't think you need a config - xml - file anyway:
Zoran's gcams for s8/Samsung
The most recent one (2nd) work here but the result is not what you could expect. I have tested a more recent gcam version that with many efforts I was able to use for taking a couple shots and it is very impressive, the level of detail, smoothing, sharpening, AWB etc does make the S8 camera much better, but I couldn't make it work further, and I have not been able to reinstall it and have it work at all since then.
I'm not sure at all those ones will give you better results than samsung's camera, the most recent versions imply android 11 or 12 or 13 I guess (tested on 13).
here is a working S8 exynos config file for GCAM, put it in your gcam/config and/or config8 and or in config7 and or XML folders, if needed.
S8 exynos xml config file for google cam
now if people have found a solution for using the latest google cams on S8 I'd like to hear from it because the benefit is huge with those recent versions, thank you
PS: in case the file host deletes it, here is the file, copy its code and paste it into a new text document , save as exynos.xml, and use:
XML:
<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<string name="pref_zoom_in_command_string">-1</string>
<string name="pref_has_checked_dual_ev_brightness">0</string>
<string name="lib_removeblur_key">OFF</string>
<string name="lib_tone_key">OFF</string>
<string name="lib_chromaLowNR_key">OFF</string>
<string name="audiochannels_240_key">0</string>
<string name="vid_ses120_all_key">0</string>
<string name="videoframerate_120_key">0</string>
<string name="pref_has_shown_longp_education">0</string>
<string name="pref_camera_coach_key">1</string>
<string name="pref_camera_picturesize_front_key">3264x2448</string>
<string name="pref_double_tap_key">zoom</string>
<string name="audiosamplerate_120_key">0</string>
<string name="raw_key">0</string>
<string name="videobitrate_240_key">0</string>
<string name="lib_chromaHighNR_key">OFF</string>
<string name="pref_camera_grid_lines_mode">3</string>
<string name="lib_sabresharp2_key">OFF</string>
<string name="pref_imax_audio_enabled_key">0</string>
<string name="audiocodec_240_key">0</string>
<string name="gawb_longexp_b">1</string>
<string name="pref_ext_mic_key">0</string>
<string name="model_tune_key">4</string>
<string name="pref_switch_to_previous_mode_command_string">-1</string>
<string name="lib_Spatial_key">OFF</string>
<string name="audiosamplerate_240_key">0</string>
<string name="pref_has_checked_cheetah_mode">0</string>
<string name="lib_removeblur2_key">OFF</string>
<string name="merge_key">0</string>
<string name="videocodec_240_key">0</string>
<string name="device_hdrplus_key_0">0</string>
<string name="vid_ses_tl_all_key">0</string>
<string name="lib_lumaNR_key">OFF</string>
<string name="vid_ses30_all_key">0</string>
<string name="pref_camera_picturesize_back_key">4032x3024</string>
<string name="pref_disable_log_key">1</string>
<string name="pref_mode_vesper_level">1</string>
<string name="pref_social_app_org_telegram_messenger">0</string>
<string name="lib_MaxISO_key">OFF</string>
<string name="lib_HDReffectIntensity_key">OFF</string>
<string name="pref_camera_enable_iris">0</string>
<string name="pref_micro_mode">1</string>
<string name="pref_has_checked_ornament_mode">0</string>
<string name="pref_release_dialog_last_shown_version"></string>
<string name="gawb_key">NEXUS_EXPERIMENTAL_2016</string>
<string name="pref_camera_hdrplus_option_available_key">1</string>
<string name="lib_Vingette_key">OFF</string>
<string name="videoframe_120_key">0</string>
<string name="lib_zipper2_key">OFF</string>
<string name="expastro_key">0</string>
<string name="pref_meteringmode_key">2</string>
<string name="reinit_cam_id">0</string>
<string name="pref_volume_key_action">shutter</string>
<string name="pref_has_seen_permissions_dialogs">1</string>
<string name="pref_link_first_time_chip_click_ms">0</string>
<string name="lib_dehazed_key">OFF</string>
<string name="pref_config_nickname_key">EdUaRdO</string>
<string name="audiochannels_120_key">0</string>
<boolean name="camera.shasta_zsl" value="true" />
<string name="lib_sharpness_key">OFF</string>
<string name="lib_underexpo2_key">OFF</string>
<string name="frame_count_key">0</string>
<string name="videocodec_120_key">0</string>
<string name="videoframerate_240_key">0</string>
<string name="lib_Exposure_key">OFF</string>
<string name="active_cam_id_back_key">0</string>
<string name="audiocodec_120_key">0</string>
<string name="dev_setting_filter_key">shasta</string>
<long name="tooltip_latest_impression_timestamp_for_cuttlefish_steady_advice" value="1618011958697" />
<string name="lib_sect_key">OFF</string>
<string name="lib_temporal_radius_key">OFF</string>
<string name="device_key">4</string>
<string name="pref_camera_resolution">full</string>
<string name="preview_key">1</string>
<string name="galley_key">1</string>
<string name="pref_exp_photo_key">0</string>
<string name="shasta_key">0</string>
<string name="tune_coeff_key">50</string>
<string name="pref_camera_selfie_mirror_key">0</string>
<string name="pref_camera_hdr_plus_key">on</string>
<string name="lib_contrast3_key">OFF</string>
<string name="fileformat_240_key">0</string>
<string name="videobitrate_120_key">0</string>
<string name="pref_af_mode_front">0</string>
<string name="expastro_key_1">32000</string>
<int name="tooltip_impression_count_for_cuttlefish_steady_advice" value="1" />
<string name="lib_sabresharp3_key">OFF</string>
<string name="expastro_key_0">1000</string>
<string name="pref_has_checked_tiara_mode">0</string>
<string name="c_t_key">0</string>
<string name="lib_clarity_key">OFF</string>
<string name="vid_ses240_all_key">0</string>
<string name="pref_social_app_com_google_android_apps_messaging">0</string>
<string name="videoframe_240_key">0</string>
<string name="pref_upgrade_version">21</string>
<boolean name="camera.gouda.shasta_zsl" value="true" />
<boolean name="autotimer_tutorial_shown" value="true" />
<string name="lib_removeblur1_key">OFF</string>
<string name="model_tune_key_1">0</string>
<string name="perf_has_shown_options_bar">1</string>
<string name="expcomp_key">0</string>
<string name="pref_storage_saver_auto_disable">0</string>
<string name="lib_smoothness_key">OFF</string>
<string name="pref_exp_astro_key">0</string>
<string name="pref_antibanding_key">3</string>
<string name="bl_key_0">1</string>
<string name="gawbratio_key">0</string>
<string name="pref_video_fps_p2018_key">FPS_30</string>
<string name="pref_camera_raw_output_key">0</string>
<string name="pref_video_fps_4k_key">FPS_30</string>
<string name="pref_has_checked_social_share_toggle">1</string>
<string name="fileformat_120_key">0</string>
<string name="model_tune_key_0">0</string>
<string name="pref_show_sabre_button_0">1</string>
<string name="pref_switch_camera_command_string">-1</string>
<string name="pref_has_checked_photosphere_mode">0</string>
<boolean name="camera.shasta.force" value="true" />
<string name="pref_exp_photo_key_0">1000</string>
<string name="hwlevel_key">0</string>
<string name="pref_camera_sounds_key">0</string>
<float name="camera.shasta.factor" value="10.0" />
<string name="active_cam_id_front_key">1</string>
<string name="pref_switch_to_next_mode_command_string">-1</string>
<string name="lib_sabresharp1_key">OFF</string>
<string name="pref_exp_ns_key">0</string>
<string name="custom_libs_key">OFF</string>
<string name="bl_key">0</string>
<string name="lib_temporaldenoise_key">OFF</string>
<string name="lib_sabresharp_key">OFF</string>
<string name="pref_social_app_com_whatsapp">0</string>
<string name="pref_camera_recordlocation_key">0</string>
<string name="pref_video_fps_cm_key">FPS_30</string>
<string name="device_hdrplus_key">0</string>
<string name="lib_zipper_key">OFF</string>
<string name="pref_camera_raw_output_option_available_key">1</string>
<string name="qjpg_key">100</string>
<string name="pref_has_checked_cuttlefish_mode">1</string>
<string name="lib_denoise_key">OFF</string>
<string name="quality_240_key">0</string>
<string name="lib_Exposuredepending_key">OFF</string>
<string name="lib_underexpo_key">OFF</string>
<boolean name="camera.shasta_psl" value="true" />
<string name="pref_camera_single_shot_sound_key">0</string>
<string name="lib_underexpo1_key">OFF</string>
<string name="pref_livehdr_key">1</string>
<string name="perf_has_run_first_education">1</string>
<string name="pref_video_fps_key">FPS_30</string>
<string name="pref_zoom_out_command_string">-1</string>
<string name="gawb_key_1">NEXUS_EXPERIMENTAL_2016</string>
<string name="gawb_key_0">NEXUS_EXPERIMENTAL_2017</string>
<string name="lib_zipper1_key">OFF</string>
<string name="reinit_mode_id">1</string>
<string name="key_social_share_opt_in">0</string>
<string name="perf_has_run_second_education">0</string>
<string name="pref_has_checked_measure_mode">0</string>
<string name="lib_contrast_key">OFF</string>
<string name="lib_ChromaNoise_key">OFF</string>
<string name="pref_exp_ns_key_0">3333</string>
<string name="key_ff_opt_in">0</string>
<string name="pref_has_checked_dual_ev_shadow">0</string>
<string name="frez_key">0</string>
<string name="lib_gamma_key">OFF</string>
<string name="audiobitrate_120_key">0</string>
<string name="lib_saturation_key">OFF</string>
<string name="lib_ShadowLightIntensity_key">OFF</string>
<string name="frame_count_key_1">7</string>
<string name="pref_has_checked_lens_mode">0</string>
<string name="frame_count_key_0">64</string>
<string name="audiobitrate_240_key">0</string>
<string name="smartphone_key">0</string>
<string name="pref_noise_model_key_0">0</string>
<string name="pref_noise_model_key_1">0</string>
<string name="pref_config_changelog_key">10.04.2021</string>
<string name="quality_120_key">0</string>
<string name="pref_camera_dirty_lens_history_key0"></string>
<string name="tune_coeff_key_1">0</string>
<string name="vid_ses60_all_key">0</string>
<string name="tune_coeff_key_0">0</string>
<string name="lib_lessworms_key">OFF</string>
<string name="pref_shutter_command_string">-1</string>
<string name="pref_video_resolution">RES_1080P</string>
<string name="pref_noise_model_key">-1</string>
<string name="pref_has_checked_gouda_mode">1</string>
<string name="pref_camera_advice_settings">1</string>
<string name="pref_audio_zoom_key">0</string>
<string name="pref_af_mode_back">0</string>
<string name="lib_HDRoveralllightness_key">OFF</string>
</map>