I've tried different setups eg. Manjaro/KDE (default), Arch/Mobian Phosh. KDE is more like a phone, Phosh is "more stable" and particularly my interest external display which is buggy.
Regarding battery I have now just started to remove them from the phone rather than putting it in Airplane mode because it still dies too fast.
The squad [0]
I have Mobian/Phosh running on SD card, see the 6 cores and 4 GB of RAM [1]
I use Tmobile for service cheap sms/call only plan
I don't use it as a daily driver yet, like install an email client and things like that. Was more interested in docked computing as a desktop. I know about Samsung Dex but I'm still onboard for a new OS, I'm particularly annoyed with forced bloat/permission issues (some understandable).