Hey,
i have the Xiaomi 13 Ultra (Ishtar),
i recently installed the HyperOS 2 update and had a lot of problems with the phone rebooting and lagging as someone mentioned here above me.
I installed today the updated twrp and dirty flashed the rom again, it seems to solve some of the problems.
I still have 2 problems at the moment, here they are:
1. Battery charging is connecting\disconnecting a lot of times randomly (if i'm correct it happens when a notification is received).
2. While i'm in phone calls and WhatsApp calls, the microphone is not working, the other side can't hear me at all.
I very appreciate all the work and hoping for a solution because the phone part is very critical for everyone i guess.