For those interested, I've gotten this response and the stability of the environment seems to be better now:
> "...removing the TEMP folder, and restarting.
> Looking at the logs before it seemed there were some issues with some indexing/caching, so the db locked up.
> But it seems like that issue was resolved by removing that folder"
The "...that folder" referenced in the text is the TEMP directory.
As previously stated, I also manually removed and rebuilt the Examine Index, which might have contributed to resolving the issue.
Anyway, not too much concrete information on what was done or why it lead to such severe problems without any visible error information.
So for now I'll consider the case resolved
Thanks to you all for sharing your experiences with Cloud 🙏