Have you checked Windows Defender? It could be blocking it. Going into the Defender settings and add the MSFS folder as an exception.
I had an issue two weeks ago. MSFS wouldn’t even show the logo. I’d get s black screen for a second and would then a crash. I tried everything, including formatting my pc and reinstalling everything several times! It was a bad week.
Then someone suggested Windows Defender. The problem was solved. I don’t use Steam (so maybe that’s the problem?) but this is certainly worth a try.
Regards
Steve