Actual running apps which I am interacting with are maybe 5. There are also server (Plex, Roon, ...) and utility apps (such as Little Snitch, Fing, Sophos, ...) which are running constantly.
Wait, I'm trying to figure out why you need these programs exactly:
Little Snitch is a firewall program that alerts you whenever a connection is made to the internet. (
https://www.obdev.at/products/littlesnitch/index.html)
Fing sounds like the same thing as Little Snitch. (
https://www.fing.com/)
I'm not sure what you're referring to by Sophos, since that's a company and not a product. But the company does provide cyber security (
https://www.sophos.com/en-us )
Why so many software firewalls, and why not use the firewall that's included with MacOS? Running multiple software firewalls is just asking for trouble in my opinion.
For the servers that you're running..
Plex is a streaming service. (source:
https://www.plex.tv/ ) I never used it myself, and I'm not familiar with it at all. But servers do use a lot of RAM.
Soon sounds like Plex, except for music (source:
https://roon.app/en/ ). Again, I never heard of it, and I never used it, but the more connections you have to the server, the more RAM you need.
It sounds like you have other servers and utility apps, because of the (...). My advice:
1. Get a separate Macintosh/ Computer whose sole purpose is to be a headless server connected to a couple of hard drives. Set it up, put it in a closet, and forget about it.
2. It sounds like security is important to you. Get a hardware based firewall. It can either be another computer (separate from the server you have), or a specialized device that is just a firewall. If it's a specialized device, get something like this:
https://www.firewalls.com/fortinet-fortigate-40f-hardware-only.html Otherwise, get a cheap Linux box. Sophos sells firewalls too.
It'll reduce your computer's RAM usage, and you'd keep your network more secure.