Well, what was shared was a lot to read .... so a follow up ...
It's not abnormal to separate mysql DB server and Moodle DB to a dedicated machine. That server not running apache. And config of MySQL attempts to use as much memory as it can on that server.
Best, of course, if code server is one hop away from the DB server.
To is it possible to off-load autobackups ... yes ... but with some effort.
One could clone the code to the DB server. Use a mount point for moodledata on the DB server. Again, Apache isn't running. Change config.php file on clone enough to allow CLI scripts to run. But with that setup, one could run the autobackups from command line on the remote DB server.
Obviously, memory of this dedicated DB server important.
So it's possible.
'SoS', Ken