I tried to run my project on new alpha and framerate is extremely unstable, varying from 5 to 60 without any reason.
I tried to create a new HDRP project and have the same problem there. Then I ran the same project on 2021.2 beta without any lags at all.
If you want me to provide you with any additional information, let me know.
I also happen to use Windows 11, maybe it’s relevant.