There's nothing wrong with just running a laptop as a server until you have specific requirements it can't meet.
Like maybe running a pi hole over wifi doesn't fill you with confidence and you really need something plugged into your router.
in which case I'd get a cheap mini-pc. even something as cheap as an N95 will handle everything you want to do here easily but you can also go the 2nd hand 1L route which can be fun too.
I mentioned a cheap dedicated server because I'm not sure when quicksync was introduced, if you need to do any transcoding at all an intel macbook will probably catch fire.
and if you haven't already then change the thermal paste. I have a 2015 pro as well and it gets real hot, factory paste can be a crap shoot if it's even making contact in the first place much less after a decade and new paste actually makes a bigger difference in performance than I expected.