I actually have an issue that is similar. My server goes unresponsive/freezes after N hours of uptime. N is a variable, so far meassured between 6 and 72 hours. I tried working around it, by auto-rebooting the server each night. But it still sometimes happen before the 24 hour mark.

Nothing in logs, so my best option is to auto-reboot at this time. 😆

I just solved this exact issue after living with it for a few months.

For me it was a bad PSU, voltage drop probably stopping the HDDs and SSDs, which knocked over the Kernel