The Xiaomi Mi 11 Ultra proved to be a very capable smartphone in our review. It is the Samsung Galaxy S21 Ultra's true competitor. However, there is still some room for improvement, especially in terms of software.
https://www.notebookcheck.net/Verdict-for-the-Xiaomi-Mi-11-Ultra-The-flagship-smartphone-needs-some-polishing.545950.0.html
Good review however I am sure that I agree on the software. MIUI 12.5.2 was just released and it is pretty good. 12.0.2 was good; 12.5.2 is better - faster with some added features. I have the S21 Ultra and Note 20 Ultra along with the Mi 11 Ultra. The Mi 11 Ultra is better in many ways hardware and features wise while running good software.