How to Determine Core Reboot Root Cause?

It appears that as of July 1, 2023, my HA System has experienced unknown reboots in the middle of the night. I’m noticing that when I check the logs, it looks as if the system started sometime between 1-4AM, but in June I clearly show history of uptimes greater than 24 hours. I have no clue as to what’s prompting the system to reboot or crash. It doesn’t seem like anything is broken as everything is functional when I access the system, I just happen to notice the uptime value is super low, which prompts me to look in the logs and see that it rebooted over night.

There are several threads in the community on how to get logs post crashes, but I haven’t found anything definitive, so I’m starting a new thread specific to determining root cause for core reboots. What can I do to determine why my system is rebooting?

I’m running HAOS 10.3 on an Intel NUC and currently on 2023.7.3.

I’ve looked through the home-assistant.log.1 file to see if there’s anything worthwhile, and I found this right before the reboot:

OSError: [Errno 113] Host is unreachable
2023-07-27 04:03:03.937 ERROR (MainThread) [homeassistant.components.hassio.handler] Timeout on /store request
2023-07-27 04:03:03.940 ERROR (MainThread) [homeassistant.components.hassio.handler] Timeout on /os/info request
2023-07-27 04:03:03.942 ERROR (MainThread) [homeassistant.components.hassio.handler] Timeout on /core/info request
2023-07-27 04:03:03.945 ERROR (MainThread) [homeassistant.components.hassio.handler] Timeout on /info request
2023-07-27 04:03:03.947 ERROR (MainThread) [homeassistant.components.hassio.handler] Timeout on /supervisor/info request
2023-07-27 04:03:03.950 ERROR (MainThread) [homeassistant.components.hassio.handler] Timeout on /host/info request
2023-07-27 04:03:03.954 WARNING (MainThread) [homeassistant.components.hassio] Can't read Supervisor data:

I’ve also filed this item in github, but not sure what else to look for that might be causing the issue. I’m wondering if it’s related to my NAS going to sleep from 0:00 to 6:00, so I’m going to test disabling the sleep to see if that helps.