UPDATE: It crashed again today, and I was able to pull some logs and check the temperature at the time of the crash.

From system log

<13>1 2024-03-13T18:30:44-04:00 OPNsense.my.home opnsense 44846 - [meta sequenceId="1192"] /usr/local/etc/rc.newwanipv6: No IP change detected (current: IPV6ADDRESSREDACTED, interface: wan)
<13>1 2024-03-13T18:30:53-04:00 OPNsense.my.home opnsense 60522 - [meta sequenceId="1193"] /usr/local/etc/rc.newwanipv6: No IP change detected (current: IPV6ADDRESSREDACTED, interface: wan)
<45>1 2024-03-13T22:12:44-04:00 OPNsense.my.home syslog-ng 10182 - [meta sequenceId="1"] syslog-ng starting up; version='4.6.0'
<13>1 2024-03-13T22:12:45-04:00 OPNsense.my.home kernel - - [meta sequenceId="2"] ---<<BOOT>>---
<13>1 2024-03-13T22:12:45-04:00 OPNsense.my.home kernel - - [meta sequenceId="138"] WARNING: / was not properly dismounted

From dmesg

arp: 192.168.1.61 moved from someMAC to anotherMAC on igc1
arp: 192.168.1.61 moved from anotherMAC to someMAC on igc1
WARNING: / was not properly dismounted
WARNING: /: mount pending error: blocks 40 files 4

I mean, I’m not saying that errors on the drive are the CAUSE of the problem, more likely a symptom, but it does look like it just straight up crashed, right?