The Xiaomi 12 Ultra is coming. It appears they can be no doubt about that anymore, as the flagship phone has now been spotted on an IMEI database, with two different sources also providing information on possible launch timeframes.
https://www.notebookcheck.net/Xiaomi-12-Ultra-Official-listing-and-leaks-tout-existence-and-expected-launch-date-of-Xiaomi-s-flagship-champion.601478.0.html