(Someone just asked about this, so in case you missed it:)
You can leave conversations on Mastodon by using the "Mute Conversation" feature. More info and instructions at:
➡️ https://fedi.tips/muting-conversation-threads-in-mastodon
This works for any conversation thread you've been mentioned in. You can also unmute the conversation if you change your mind.
@feditips Good tip. thanks.
I'd like it if I could mute conversations I haven't been mentioned in too. Those are the ones I find more irritating. Esp'ly when they involve one of the super boosters whose content I often want to see but is currently boosting a whole thread of stuff I don't want to see ...