@sven I will share you my experience. On Jan, I have tried to mess around like what you have said with my device Google Pixel 3a XL by trying other OS (Droidian) which was available as a second option after UT.
I've installed it with success and ease. Honestly it is quite interesting, but still lags and lack of features. The idea is good comparing to real desktop version.
I have decided to go back to UT 20.04 OTA-7, by flashing the device to Stock Android 9 and then commencing installing UT via UT Installer.
All steps were correct, only when reached Recovery Mode and waiting for files to be installed, it got stuck for ever there, just waiting and scanning devices.
I have tried three times with no luck to install UT back to my device.
I have tried four times Android 9 and Droidian with success and no issues.
This is my experience with messing around with UT.
Am waiting to see 24.04 to be released to install it back again to my device.