To that question, idk. Postmarketos is more standard, using the mainline kernel (and having the downside of porting the android kernels, like my smartphone, a Redmi Note 9s, having 4g bugged because of the kernel), having normal applications installed with apk, using the same tools as desktops, but UT uses a hybrid approach, it uses the hybris and halium, that is a compatibility layer on top of the android kernel, but it's heavily built towards snaps, immutable images, that kind of stuff, waydroid didn't work, it seems bugged on my phone as well. Droidian is more standard debian, but with hybris, but I updated the system and it didn't boot, so I couldn't test it, but on my opinion, phosh on droidian > lomiri.
The gold standard to me would be postmarketos with hybris or droidian working well, but only time will tell. I think it's best to shop around.