I definitely understand not wanting to spend money, and dont have any more suggestions really hope the amd motherboard works out well for you if that’s what you decide on.
One thing I would like to say though, is that sometimes you need to spend money to make money. It cost maybe 80$ for a used mini PC on eBay (corporations literally throw them in the trash after every few years). Lets say your current setup consumes 10 dollars in energy per month to run, after a year its 120$ in energy in upkeep. Let’s say a mini PC cost 5$ in energy per month or 60$ per year. Meaning while you may have invested 80$ initially, its nearly made up for itself in power savings after only a year. And those numbers are probably even better in real life as a mini PC is almost certainly uses much less than half the power of a regular desktop/server.
A raspberry pi 5 could almost certainly do most of the things you describe, and its also around 80$ (i think) its extremely fast and has great IO speed. Check out ExplainingComputers review of pi 5
Another advantage of the pi particularly the zero is that it can potentially be powered by solar power and a few batteries, cutting power cost completely. LowTechMagazine has a solar powered version of their website with public info on power stats which is really cool solar.lowtechmagazine.com/power
Again, I understand not wanting to spend $ however if you are in a good enough financial position that a hundred bucks is expendable income, consider retiring your old hardware for something newer and much more energy saving, and probably just as good for your service needs.