There is a lot of collaboration between the different instance admins in this regard. The lemmy.world admins have a matrix room that is chock full of other instance admins where they share bots that they find to help do things like find similar posters and set up filters to block things like spammy urls. The nice thing about it all is that I am not an admin, but because it is a public room, anybody can sit in there and see the discussion in real time. Compare that to corporate social media like reddit or facebook where there is zero transparency.
I think that user donations are easier when an instance has a good focus. There are some other instances I can think of where the donation model has been enough to cover things. In addition to feddit.dk and beehaw, an instance I use most of the time, ani.social, is more than covered by donations last I checked.
It looks like @hitagi@ani.social even took away the donate link in the sidebar.Never mind, I am just blind. I didn’t notice the little Ko-fi badge at the bottom. I was looking for a text link.