If you use an instance just for yourself, it doesnât actually decrease the load on the main servers in any way.
Thatâs not completely true. Yeah, it still loads another server a bit, but the server-to-server federation traffic is much more lightweight than the client-to-server traffic that would be involved with you having an account on that server and accessing it that way.
But yeah, multiple, equally-sized communities on different instances is the ideal situation. The only sticky part right now is FOMO because youâd have to constantly watch for new SelfHosted communities and join them. Hopefully some frontend tools come along soon to make joining/managing multiple communities like that more streamlined.
Yes, ideally youâd want to have a few large communties on each instance and not all topics with a single userbase on one. This not only decreases the load but also prevents scenarios in which a single admin starts to capsule their instance with a large userbase away from the federation.