(Apologies if this duplicates my earlier post but I'm trying to submit this again since I can't see my previous message)
Thanks for the great set of guidance and tips.
I've belatedly discovered that, at least in linux mint 22.1, by default, it runs an apache webserver, serving a placeholder web page for connections to
127.0.0.1:80. Since this results in a few processes that use up a small amount of memory (around 15MiB) and adds to the set of startup services, and since serving local web pages is something I suspect plenty of users have no need for, it seems like a good candidate for a mention somewhere in this guide's optimisation tips (and is something I don't remember reading when last following them... apologies if this is already covered).
The service could be stopped from auto-starting -
sudo systemctl disable apache2and even the apache2 webserver packages could be removed entirely -
sudo apt remove apache2*