Issue Out of memory but plenty of memory

[pleskpanel]

Thank you all, I'll think about migrating to something else. In any case a dedicated server is way an overkill.
The current host has told me they guarantee the 8GB 100%, no matter what.

Besides, I checked with the online mySQL calculator and with current settings (i.e., 2GB innodb_buffer_pool_size) I reach just 3.2GB.

What about upgrading to Almalinux 9 as an attempt of last resort? How complex is that?

If that's the case, then it's likely an abusive or malicious bot/vulnerability sniffer that causes your memory usage to surge so much that OS invokes the OOM killer to avoid kernel panic so you might want to check access logs if you want to try and track it down.

Almalinux 9 is solid and has a great long runway!