fwiw I got onto cohost a few months ago and have really enjoyed it.
Because it's a smaller community with no "algorithm" intentional discovery actually happens. I use hashtags to find stuff, and other people have found my stuff via hashtags! I only started sharing online this year and so that second bit is huge - it's night and day between twitter and cohost[1].
The site actively tries to avoid the status games that other social networks play. You can't see follower counts or like counts (including your own) and instead get notifications like "several folks liked this" (with a list of who did). There's no easy way to answer "how big is this person's following" when looking at their profile.
I think this adds up to a site that feels more like a community. Comments are typically either nice/encouraging or interesting and folks comment a lot. It's easy to find cool posts. Not having metrics is freeing. Many of the folks that post are there to share the cool things that they do.
It's not a replacement for twitter, but it's easily the site that I'm the most excited to share stuff on - especially early WIP stuff (I shared something fun last night!)
[1]I shared an early version of Flappy Dird[2] on cohost and got some real engagement and it felt great. Flappy Dird ended up doing pretty well on HN; I doubt I would have polished it as much without the early cohost support.
[2] https://eieio.games/nonsense/game-11-flappy-bird-finder/