I received the android 12 update on my zenfone 8, apparently everything is stable, I didn't notice any bugs or other problems, I thank the asus team for the effort. The only point I've noticed so far, was a slight nerf on the Multi Core of the device, on android 11 with the geekbenchmark, it scores 3640 on the multi core, on the A12, I don't see it coming out of the 3300. Both tests were made with the "high performance" profile. With an optimization, I believe you will be able to resolve this issue in a quick time.
Ok, so 24 hours for me as Android 12. All apps are working perfectly, all menus and functions working properly. Didn't noticed any bug for now, except a little stutter like a slight delay on Samsung browser at 90Hz, but only on pages with a lot of text. It's kind of annoying, like not responsive as in Android 11. Battery seem OK, didn't noticed any difference, not in worse or better.