Sometimes I have to kill gnome shell

Using Ubuntu 20.04, sometimes the screen will go black and I can't do anything. I can still see my mouse pointer and move it around, I can drop to a text console with CTRL+ALT+F4 and back with CTRL+ALT+F2 but it's not working right. I've found that if I get to a text console and login and then find the number of the gnome-shell process with "ps -ax | grep gnome-shell" then "kill -9 " it will close the gnome-shell and after a few seconds the system will relaunch it, bringing the system back to normal. It doesn't always work, but sometimes it's a lifesaver when it goes non responsive and you can save what you were working on.