Put your file to /data/user_de/0/com.android.phone/files/ but Vo5G switch still does not appear.
But it gave me some hints! The "carrier_config_version_string" in your file is chinamobile_cn-43000000
048.12.
After put the file under the path, reboot, and check the SIM settings, the string in 'carrier settings version' is still chinamobile_cn-43000000
706.58, which remains the same as my file!!!
The .xml file is the same as yours when I pull it out, which means the file is saved to the path correctly.
To sum up, my device reads the very origin .xml file from the carrier (though the file has been edited many times, no Vo5G boolean sentence in it, of course), even after the file is edited and even is replaced by yours. To solve the problem, is to find out how to make the device read the edited file rather than the original one from the carrier. Could you give me some advice?