Word out of the Windows Gods is if you have Windows 11 Update (KB5063878) Released around 8/12/2025. Its mostly a security update but it can destroy SSD drives. When transferring large amounts of data, reproducible errors occur when saveing to certain SSDs with certrain controlers. This can lead to data loss. Corrupted files, or completely failed drives.  The system can crash and when you go to file explorer the SSD card might not appear.  Rebooting doesn't always fix the problem. And some have reported HDDs drives failing or vanishing as well.

Recommendation is to BACK UP ALL YOUR DATA. Uninstall the update. Goto Windows Update> Update history to see if you have it. And then uninstall the update.  Disable Automatic updates for about 5 weeks (that is the recommendation at this time).

Sure wish Microsoft hadn't let so many of their testers go, if that has any part of why this has occured.