Hi,
I flashed the latest LineageOS 17 treble GSI Image (Android 10). For those interested, it works well with no crashes, errors etc. Everything works smooth. The battery drain may be bigger (have to test this some more).

My issue is the following: before flashing, I backed up all the system and user apps with Titanium Backup. As I flashed a generic image, what are the apps that I need to restore in order to have the Walkie Talkie function once more? I cannot find the PTT button in this firmware. 

Can anyone help me with this?