So I recently bought Pixel 3a to try the waters of Linux mobile. I installed UT first, but I wanted to try others as well so later installed postmarket OS. While I liked it, UT functioned bettet so got back to it. That's when the issues began.

Now when I restart, it sometimes reboot but usually just shuts down. When it reboots (or I boot it up) it gets stuck in a loop:

Boot -> google splash screen -> UT splash screen (rarely it doesn't even reach it and reboots after google screen) -> freezes (sometimes I get white screen or just flashes of white screen) - reboot - repeat.

This gets way worse with Libertine set up - it goes through after a number of cycles, then just gives up and finally doesn't reboot and stays shut down. And when I have a package installed in Libertine (tried with Firefox) it feels like it gets worse still and I'm unable to get to login at all.

Rebooting through recovery mode usually gets the device to fully boot up successfully. Did factory reset and also tried flashing UT again, issues persist.

Not sure if relevant, but when I was flashing UT the second time around, the installer didn't register the device automatically, had to select manually.

Weird thing is it worked fine the first time - but after I tried postmarketOS and went back again is when the trouble started. Not sure what I could've done wrong though and no idea how to troubleshoot. I'm pretty new to Linux, very much on a regular user level.