I have a mastodon account, I still check it occasionally and I've tried making it work a year ago, being active on it and following either people or hashtags. I also tried other networks like bsky and cara, or mastodon through kbin integration. None of them really worked out.

I didn't have an issue with the technical side as much as with the community and its mentality. They all have this persecution complex where everyone is out to get them and destroy their way of living. They simultaneously claim it's better and more morally superior than twitter while also responding to any questions or feedback with "if you don't like it GTFO". Most of the posts I've seen on mastodon seemed masturbatory and/or talking about other social networks and why are they bad than why is mastodon actually good. In many ways it was more toxic and negative than my carefully curated twitter feed. There's also as much doom and gloom as on twitter, if not more, when it comes to politics (or at least, it's harder to hide it).

The content in general was bad and boring but I don't know if this is because of the type of people that are on it or just because the lack of algorithm means I will see any random person's ramblings next to the biggest breaking news that I'm actually interested in. There is a lack of innovation in this area and it makes discoverability and content curation terrible, I don't need an algorithm to read my mind but at the very least I wish it could separate trash from actual popular topics.

I found some interesting niches when it comes to FOSS developers and tech but I found next to no actual game devs, artists or content creators on it and even the usual "copy content from twitter" bots were unreliable and uncommon.

TL;DR Mastodon seems very very niche and is not currently viable as a general replacement for other social networks, and IMHO due to the community culture there it's never going to grow into anything else either.