HA crashing completely

Hi all, over the last month or so I’ve been seeing my prod HA fall over, to a point where I have to power cycle it.
It still remains pingable, but Home Assistant and the observer become unreachable, other addons also seem to be unreachable as I’m unable to ssh in.
I can’t find anything in any logs (so far) so wondered if anyone might be able to point me in the right direction?
For info, I’m running on SSD so it won’t be a card issue, although I’m by no means ruling out any potential hardware issues. I’d just like to track down the culprit and fix/replace.
Thanks!