@falken when my btrfs volume died it turned out to be due to faulty RAM. It was because of all the extra checks with btrfs that the problem showed up in the fs first as checksums stopped matching.
@fosstian would be shocked if brand new @frameworkcomputer with their own RAM was bad. Memtest86 at install time was clear
@fosstian I did run one pass through again, just to be sure, thanks !
@falken @frameworkcomputer fair enough!