Anecdotal, but I’m working through something very similar. I have 2x 1TB M.2 drives with heatsinks. One is a WD Blue, the other is a Microcenter Inland Premium. WD is a slower one, at 500MB/s read and write, while the Microcenter is my gaming one at 3500MB/s read and write (roughly).
A few weeks ago after setting my rolling cache to 500GB on the WD Blue one I got a “Boot drive not found” error. After reinstalling Windows and purchasing Easus Partition Manager, I was able to recover my partitions. It just seemed to kill the Master Boot Records. Anyway, that error then happened again within a week.
I’ve now downloaded MSFS a grand total of three times in three weeks, absolutely killing my bandwidth quota, and now it won’t even run. It checks updates, starts the load screen with the blue bar at the bottom, then just CTDs. Since it’s a fresh Windows and a fresh install of the game, I’m out of ideas on what might be causing it. CrystalDisk shows hard drives are healthy and have not overtemped.
Anyway, I’ll start my own thread with this info since I don’t want to hijack yours, but I wanted you to know that others are experiencing similar issues.