Just to close this out, and not be "that guy" (https://xkcd.com/979/), I ended up just rolling the
kernel back to the Fedora 35 kernel (5.14.10).
Without a good way to isolate where the problem is (between XFS & LVM), I really didn't want
to waste time tracking this down, and restoring my system every couple hours. I'll try again in 6
months or so and see if maybe it's been found and fixed.
If the old kernel works, that points to the kernel rather than a hardware issue. If your
hardware is widely used, others will encounter the same problem. Searching
for issues with linux 5.18 (any distro) and your specific hardware may find other victims.
There were "bug fix" changes to xfs in 5.18:
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