Thank you Sac23 and Afaneh92. I have a bl unlocked SM-N986U (U.S. carrier = AT&T) and am on Sac23_N986U_TWRP_Flashable_ROM_1_17_2021. All is VERY good (thank you), with one notable exception: I cannot get, and never could get, a 5G connection (where partner with a stock ATT 5G reliably gets 5G on her phone at my location). (My 4G-LTE/CA recep is excellent.) ATT SIM card is new and 5G. ATT 5G bands are: n5, n77 and n260.
(1) Does the 1-17-21 ROM have any issues with 5G?
(2) Specifically with those bands?
(3) Would the “Sac23_Custom_Roms_XDA_10_25_21_N986U_OCT_Patch”
fix this 5G issue?
(a) If yes, what are ODIN settings, and will the update delete installed apps, root/Magisk/TWIRP?
(b) If no and I install ATT Stock ROM from Sammobile, will I lose root/Magisk/TWIRP?
(4) If I install either 10-25-21 or ATT stock ROM, would I able to restore 1-17-21 Sac23 via TWIRP from TWIRP backup, and without losing apps and root/Magisk/TWIRP?
Thank you so much in advance for your help. Will donate for a complete answer to the above. OK to PM/Telegram.