I just set up synapse last week. The config file has 93,000 characters in it, which i joked is worse than IRCd. I'm running it on gentoo, pretty bare system, probably equivalent to double an rpi4. I did notice that the database file grows quickly. Currently the entire machine is using 272MB RAM, 0.8% CPU peaks, 0.01 15 minute load average.

Every part of setting up a server that will federate/host repeats again and again that you need a TURN server (and they recommend coturn) - which is another 26,000 character config file - in order to do VOIP. If you've ever run or used a pbx before, STUN is needed 100% of the time for nat traversal between clients. Coturn even says it won't run if it's NAT'd (it will, but that's irrelevant to most people.)

This is the fourth concurrent tech trial of chat daemons, with rocket.chat and mattermost being a couple of the other ones that we're testing. synapse/element/matrix has the benefit of forced e2ee by my configuration. I don't know of any other matrix federated servers, so i haven't tried that yet, but an associate says it works on my configuration - which means it's not as big of a pig as i thought it was based on the outlandishly, comically large config file - where whitespace matters!