The Xiaomi 12 Ultra is almost definitely on the way. The Xiaomi Mix 5 series, however, may have been ditched, as a new report appears to indicate that Xiaomi has now cancelled plans to release the phones.
https://www.notebookcheck.net/Xiaomi-12-Ultra-to-replace-the-Xiaomi-Mix-5-in-surprising-turn-of-events.612910.0.html