We really need more information. When exactly does it CTD? You said initially “everywhere”, but then since you did the reinstall behaviour is better but still CTD. When specifically. Which aircraft, which location?
Personally I’ve not had a CTD since version 1.8.3 which fixed the USB crash. Do you restart the computer or the sim only after a CTD. I would strongly recommend a full PC shutdown/restart. When I was getting crashes, after the first one, if I didn’t do a full restart, they became more and more frequent.
Have you anything in the community folder?
Can you fly the training missions? The landing challenges?
Latest nVidia driver version?
Are you running anything in the background? MSI afterburner caused crashes for a while (fixed now I think)
Please post all your settings here, including nVidia control panel settings for MSFS
What resolution? Multi-monitors?
Disable multiplayer, AI traffic, and ATC voice, don’t give controil of the ATC to the co-pilot. All these are knonw potential CTD causes.
Have you tried the suggestions in this thread: