I decided to give Mastodon another shot here recently, I found exactly one promising leftist instance, mastodon.lol. Bills itself as an "LGBT-friendly antifascist mastodon instance"
I watched another user get banned for saying that Azov were neonazis and I got banned for sticking up for them, then as part of his 240V power trip the admin posted a pity thread where he claimed we called him literally Hitler.
The only other leftist instance I saw welcomed all socialists except "authoritarians" so I assume it's either a socdem or sectarian anarchist instance.
TL;DR - Mastodon hasn't changed at all, it's still ran by power-tripping micro tyrants
I think twitter/masto is the way it is because it prioritizes the individual user feed. Blogs are similar, but you legit have to effortpost to maintain a blog. Microblogs just run on memes and vibes. People like following powerposters who entertain them and pretty people (to the point some transfems use masto like a dating service).
It's possible to form a nice little friendgroup on there, but beyond that advanced discussion feels impossible. Lemmy's success in promoting longform discussion is in de-emphasizing the user and emphasizing the post/comm.