Yep, it is a Raspberry Pi 4. Thanks for the link. I think I’ve covered points 1-4 on that list, now I’m at 5 and seeking help in interpreting the relevant parts of the log files.
If one does not see any obvious stuff in the logs, I will follow the route outlined in 2024.5+: Tracking down instability issues caused by integrations - Community Guides - Home Assistant Community (home-assistant.io).