I like the concept of the fediverse, just like I liked Fidonet back in the 80’s (that allowed BBSs to “exchange” both forum contents, called “echomail”, and private messages).
I have some issues on sustainability (hosting costs money, moderation and system maintenance can be a pain) and the “donation” model. My solution is that while I host for myself, and don’t really mind having some guest on my platform, I don’t take / accept donations - ever. My instance dies the moment I don’t have the resources to maintain it (money, time or patience). The main reason I don’t take donations is really simple: I don’t want to owe anyone anything, this is not a job or a burden I have to carry.
I have been hosting systems for 35+ years, and it’s all good with no money involved. It’s a blast dealing with the tech, really love it. Most of my systems and either one or two users (me and the wife). :-)