• DNS adjustments aren’t needed if you do .well-known delegations which is easier
• Can recommend continuwuity, it runs much better on less resources. Lacks certain features compared to Synapse but overall good
• Notifications (and read markers) depend on client-specific black magic to work
• Federation do sometimes silent-fail completely, you can reset continuwuity’s cache when that happens. But full room history convergence needs patience
• Don’t join large rooms unless your server can handle the load
• Don’t host public rooms without modbots

The many small bugs make Matrix still bad - I wouldn’t recommend a non-tech user unless accompanied by a 24/7 admin. It is trying to improve but very slow because of reasons