Hi there, i rollback from OneUi 3.0 to 2.5 with no problems, you just have to make sure that the binary and the bootloader are the same and you are ready to go
Same problem here, I installed android 11 and I did not like that the aniations were 10 milliseconds slow so I went down to android 10 with OneUI 2.5 and I feel that the problem persists