Try to go into twrp, wide data and cache. RebootFull of bug on Mi9T. Gallery and camera apps crash after few seconds, Chrome Is really slow...
I come from A9 to A10 to A11 always MIUI xiaomi.eu betas and always dirty flash. Only minor bugs sometimes.
Try when update follow this sequence: wipe system, dalvic and cache. Install ROM. Wipe dalvic and cache. Reboot system. If I see some bugs after some minutes playing the ROM: I wipe dalvic and cache in twrp and reboot
No problems doing this till now.