I admin and use a Mastodon instance. It takes a while to get used to the differences from Twitter, but it's far more polished than people seem to expect. The reading I tend to recommend if people have questions is Darius Kazemi's https://runyourown.social/
Another admin here, and yes I agree. But one major aspect of fediverse, that people rarely talk about when promoting it, is the spam. To summarize my impressions over the last 5 years I'd say there is no way to run a big open instance without funding. The best way for small single actor instances to survive is to be invite only or approve each member account. And even then I'd suggest using Geo blocking to fence off…
I really like the way social.coop, a cooperatively run instance, handles this. Because we're all just pooling a little bit of money (1GBP/yr for most people) we can run a service cheaper than we could run it ourselves if we're renting a VPS and there are enough people interested to create a rotating moderation team, so we rarely get too much spam from other instances. So far a cooperative model has worked very well for us; no donations required, just splitting up costs in the cheapest possible way so that no one gets burned out or feels like their money is carrying the instance!