Not who you asked, but I figured I'd pitch in. Hexbear.net has a good amount of AnComs, as long as you aren't sectarian against Marxists. It's a left unity space, it's where I have my other account. As a Marxist-Leninist, I find Hexbear is generally far more chill and less argumentative because there's a 0 tolerance rule for transphobia, bigotry, liberalism, etc.

Lemmy.ml is far more argumentative due to being more broadly federated, and isn't explicitly anti-Capitalist. I mainly stick here for outreach, not to have a good time or anything. You have more visibility sorting by all, and can access Hexbear from Lemmy.ml if you don't want to make an account on HB, though you lose access to emojis and other HB specific features, like easily accessing the Megathreads for News, General chatting, etc.

You probably wouldn't like Lemmygrad.ml, it's explicitly Marxist-Leninist and is sectarian against Anarchists. I enjoy it, though I don't have an account there. It's accessible from Hexbear.net and Lemmy.ml.

lemmy.dbzer0 is more piracy focused, and has an Anarchist bent. It's accessible from Hexbear.net and Lemmy.ml, but can't access Lemmygrad.ml.

Slpnk.net is socialisty, focused on the Solarpunk aesthetic movement. It can't access Hexbear or grad, but Lemmy.ml and dbzer0 are connected (I think dbzer0 is, at least).

My advice? Browse each locally for a week without making an account, see what sticks. There's no downside to making an account or abandoning your old one, really.