I’m not on any of the services currently, but I have tried Mastodon in the past and point 4. was what made me bounce off it. I know Mastodon flaunts its algorithm-free feed as almost a point of pride, but as a user it just doesn’t do it for me. I could not get it to serve me the type of content I wanted the way I wanted, and it just felt like way too much work for what I was looking for.
Does following a community spam your feed with every reply to every thread in that community, or just with new posts?