the phone supports android 9 and 10
there are some official roms and others are not you can see this on xda
Derpfest, ExtendedUI, PixysOS, Lineage 16, AospExtended, MSM Xtended and others
you can check the roms of this device here
almost all are officially maintained
I saw some problems with this device, most were on Android 10 I believe Android 9 is very stable
this information I believe it can help
[Use the Branch Lineage-16.0]
Device Tree - https://github.com/RevanthTolety/device_xiaomi_onc
Vendor Sources -
https://github.com/RevanthTolety/vendor_xiaomi_onc
Kernel Sources -
https://github.com/RevanthTolety/kernel_xiaomi_sdm632