to be sure: have you Geforce Experiance with Auto-Optimizing enabled ? Its not known that MSFS do such changes, but your post is the second I read now, so.. we should have an eye on that 
Asobo updates were changing all kinds of settings the first few updates. They got better about it, but one seems to slip through now and then. There are sooooo many settings that it’s hard to keep track of all of them.
yep, we know some settings changes some times.. but the DirectX setting would be new. Can you report back if it happens again ?
My experience is probably the exception rather than the rule, but I just started getting this CTD screen today. I fixed it by replacing my graphics card with a new version of the exact same one that I already had (Gigabyte Nvidia RTX 3060 w/ 12GB RAM). Apparently I had a subtle hardware fault in a card that otherwise seemed to work 99.99% of the time.
That said, this wasn’t my only malfunctioning game with the old card. Horizon Zero Dawn started to CTD during load screens in December of last year. One other game CTD too, but the others I played all worked fine. Even FurMark passed on a 4K monitor. No amount of driver or settings twiddling could make a difference on any of the ones that crashed. What pushed me over the edge to figure this out was it starting to happen with MSFS, given how much $$$ I put into MSFS control peripherals.
Anyway, maybe swapping in a new card may be a useful experiment? At Best Buy, they have a 15 day return policy and my plan was to return the new card if it didn’t fix the problem and get my money back. Lucky for me it worked – except now I’m out $$$ for the new card Oh, and all my recent malfunctioning CTD games like HZD are fixed, not just MSFS.