I bought a workstation from Titan computers around 1/2020 (dual EPYC cpu).  After about 1 year it stopped working.  I could ssh to it, and almost any command would return Input/Output error.  Unfortunately journalctl gave input/output error so I can't see logs.  cat /proc/partitions did not show any nvme device (the root device) on which the OS was installed.

I replaced the SSD with a samsung 980 pro.  Reinstalled fedora.  It then worked a few weeks, then the exact same symptoms.

I replaced the SSD with another samsung 980 pro, this time with heatsink.  Reinstalled fedora.  It worked a few weeks.  Then same symptoms.

Then I replaced with a 4th samsung 980 pro, but this time instead of using the M.2 socket I used a pcie-m.2 adapter (in case something was wrong with the m.2 socket).  Also added a surge protector outlet for good measure. Reinstalled.  Watched the smartctl.  No errors.  Temperature was always low.

Now it's failed again, exactly same symptoms.

Any ideas?
Thanks,

Neal