While your server most likely isn’t powerful enough to handle large rooms such as that one, if you would still like to try and get as much performance as possible you can look at this synapse documentation page
Definitely wouldn’t use windows server for homelabbing, instead consider some sort of Linux. For DNS I personally use pihole unbound which is pihole with unbound as an upstream dns server allowing for the best of both programs! Conveniently, this GitHub repo will allow you to easily deploy a working instance of pihole+unbound for use within your homelab.