System unresponsive, crashed, I found "^@" in syslog

So I recently transferred my hassio from a Raspberry Pi to a Protectli J1900 ( the system is much faster and more responsive however, a couple of times now I tried to pull up home assistant and it was offline. I troubleshot it down to the machine and when I hooked up the monitor it wouldn’t display anything. The keyboard also would not respond (caps lock, num lock test). Anyway, I held the power switch and hard booted it. Then it came right back up.

When reviewing the /var/log/syslog file for clues I found this:

That occurred right where the system hung before it started to log the reboot. This was Dec 9th 7:50am, I caught it by 8:00am. I saw this same thing before about a week ago but there were many more ^@ symbols. Presumably, because it was a much longer time between when it went down and when I noticed it was down. I searched Google for what the caret-at symbol means and I found this posting:

Which says that those are “zero-byte filler” because the system knew how much to write but not what to write. Anyway, I’m wondering if anyone knows of a good way to troubleshoot this; or should I just bite the bullet and invest in something more stable.