Here is an older post I made about all the issues I experienced, there's a lot from me in the thread as well:

https://www.reddit.com/r/oneplus/comments/jgr2n2/new_8_pro_owner_upgraded_to_11_immediately_bugs/g9wsttk?utm_source=share&utm_medium=web2x&context=3

I upgraded to OOS 11 when I first got the phone (11.0.0.1 or something, was the first release of OOS 11), and I have PTSD from it. I don't doubt it's been improved since, but I came from iPhone after 11 years and did not want a similar "flat and spacious" design. I came to OnePlus for stock Android. That's what sold me, an iPhone user for over a decade. That's what the people above don't get.

Plus the amount of grey color in OOS 11 made my green tint issue so much more visible. Add the plethora of bugs from above, and it was NOT a great first Android experience for me. So I downgraded to 10 and it's been amazing being on the last stable 10 firmware.

However, I just got my screen replaced (got it back Monday) and they gave me a gen 2 screen. Now I have no green tint at all (plus 60hz runs smoother and the fingerprint scanner is slightly faster), so I may upgrade to 11 in a few months when it's been worked on.