Crash after crash after crash - What's causing it

Thank you for this. I have tried.
-Vanilla State (re-download all 130gb+)
-Delete user profile in steam
-Uninstall, reinstall MSFS
-Community folder empty
-Downgrade graphics card driver to working
-Upgraded graphics card driver to latest
-Updated BIOS
-Updated windows version

How do you run the sim offline if it is checking on the restart? I tried turning off the internet after it have booted (installation manager window), and still nothing. Unfortunately, I can’t refund anymore. I will if I can.