As others have said, remove everything from the community folder and see if the CTDs disappear. If they do, add a couple back in at a time and fly until you find the one that’s causing it.
If removing everything from the community folder doesn’t fix it, then uninstall all marketplace purchased addons from the Content Manager (don’t worry, you don’t lose them and you can reinstall them just fine). If the CTDs disappear then add reinstall a couple at a time and fly until you find the one that’s causing it.
If that doesn’t stop the CTDs, then make sure there are no modified files in the official folders. Many times people modify/rename/remove a file inside the official folder (never remove or rename a file without making changes to the layout.json that points to it) to make a change to the sim (taxi ribbon modifications, remove or change text, etc.). Put back all original files in the official folders and see if the CTDs disappear. If they do then you can slowly make your changes again until you find the one that’s causing it.
If all that fails to find it, then it’s likely something external (video and hardware drivers, hardware conflict, external software, etc.)
Check out and follow the MSFS Zendesk page at https://flightsimulator.zendesk.com/hc/en-us/articles/4406280399250-All-versions-Crashing-CTDs-issues-Basic-Troubleshooting and also look over the items presented at Procedure to solve an issue step by step