Sketchup 2021 crashing on mac 11.1 big sur (bug splat )

Try following the steps I gave in this answer:

If you don’t still have the 2021.0.1 DMG in your Downloads folder, you can get it from this link:

https://www.sketchup.com/sketchup/2021/SketchUpPro-dmg

When that has downloaded, if the disk image window doesn’t appear automatically, double click on the SketchUpPro-2021-0-1.dmg file in your Downloads folder, and then you are ready to follow the steps I gave.