I have the same problem. Using MacBook Air 13 inch (2015). I think the problem is some sort of nvme/ssd putting to sleep too often or snapshotting current memory on ssd/nvme then resume from there. After restart or resume safari and other apps needs a lot of time .... like everything is frozen for 20-30 seconds even typing password at screensaver ! Catalina was super fast ! At least 2 times faster. Wonder if i can go back from my Time Machine ? Problem is that system firmware was also updated .... and the problem may be there too ?!

Same here .... Macbook Air 13. Playing league of legends is very bad.... i even can not pick my heroes ... always circles .... everything freezes until someone picks something .... very bad bug .... how you release such thing ?!? Apple this is not 1984 ! You must immediately pull back the update until you fixed it properly .....

These locking are not good at all !!! For example i would like to edit /System/Library/LaunchDaemons/tftp.plist just to add -l option for logging to system.log and it is nearly impossible !