I have had this issue for a while and I'm thinking it's to do with disk space.
So im currently editing obviously and I put in a clip and I can move the mouse and press buttons etc but it's not until I remove the clip from the project when it starts to work again.
Premiere Pro is on my 500gb ssd but everything else is on my 1tb hd
This clip was a photo but then I put in a 500mb ish video it's fine the same has happend the other way round too which I think is a computer issue. Don't know what or how to clear stuff if it is though.
Win 10 by the way
Premiere Pro 2021