Hi,
I have the same problem, with 11T Pro too. As I can see it is an older issue, not just with Xiaomi, and everywhere the recommendation was to turn off Always-on display at Settings > Always-on display & Lock screen. There were a lot of positive feedbacks in the case of other brands, even from 2020, but not in the case now, with Xiaomi MIUI 14. It was not working for me neither.
I was thinking on this and I hope I found a workaround.
I relized, after turning of Always-on display, that sometimes Android auto is working only for 1 minute, then freezing, sometimes it was working for 15 minutes, then stopped working...and I realized it is still in connection with Always-on display, but in an other way. There are other features of MIUI, I assume utilizing the same background processes as always-on. For example notifications. So I turned off Notification effect at Settings > Notifications & Control center > Notification effect > select none and just in case I turned off charging animation too at Settings > Always-on display & Lock screen > Display charging animation after device is unlocked.
Today Android auto was working for me continously for 40 minutes, without freezing, without flashing.
Let's give it a try.