When I am resizing pictures, the layer being resized is super quickly changing size on its own - getting bigger and then smaller, bigger, smaller etc. which makes it hard to adjust it to the right size apart from being annoying.
Turning off Graphic Card Processor helped in speeding up overall performance, but not with this issue.
I did not have these issues before Big Sur. I was waiting with this, because I hoped that restarting the computer several times and allowing it to adjust to Big Sur would change things, but it did not.