I sometimes feel annoyed when I bump into some software-related freeze (camera app freeze/crash from time to time, for example), but at least you can unlock the bootloader and grab some unofficial ROM. The problem is that I use it as my daily driver and a custom ROM would not allow me to run banking apps and such...
After this update, most of the stuff flows nicely. Very nicely, in fact. Also, my personal approach is to drop the multiple screens and use groups so I can access all the apps from the home screen. It works like a charm and looks great.
Android One made me love the Mi A1. After the initial "What is this crap?" shock, I somehow managed to live with MIUI by avoiding the weak parts. Check the XDA page that I linked to in the article. I would try LineageOS for stability and the ability to customize it myself while being as close to vanilla as possible (LineageOS 17.1, based on Android 10, works like a charm on my old Mi A1, which is now tortured by my 10 yo daughter) and Descendant XI for all the goodies included in it (see my hands-on with this ROM for the Mi A1 here - https://www.notebookcheck.net/Android-11-on-the-Xiaomi-Mi-A1-via-Descendant-XI-An-interesting-ROM-with-a-few-unique-features.520132.0.html).
Thank you for your reply and please do come back here after you manage to put a good rom on the thing! It's a pity that they managed to do such great work hardware-wise and they don't offer Android One as an option via the official channels - I am sure many of us wouldn't mind paying a small fee of 10, maybe 20 bucks to have access to that option.