It has been quite a while since anyone has tried to solve this issue, and from what I have been reading on https://forums.sketchup.com/t/sketchup-2021-crashing-and-wont-reopen/143719/13 I am not the only one with the same issue.
It did work shortly after installation, after two or three days it crashed and I have not been able to run 2021 at all. I can still use 2020. I use Sketchup for my practice on a daily basis. I work for the County of Los Angeles Parks and Recreation as their inhouse Landscape Architect and use Sketchup and Lumion to present my Park designs. I also use it in my private practice and when I teach at UCLA in their Landscape Architecture Program.
Perla Arquieta ASLA PLA
205 Ruth Ave. Venice, CA 90291