Quick toggle to hide servers(+channels?) with no new messages

I'd like an option to have servers only appear on my sidebar if they have new messages (the notification dot).

Sometimes you wanna chat in servers where nobody's said anything to start it, sometimes you just wanna keep servers unmuted for occasional messages to reply to, but don't want them to take up too much space.

In most servers I want unmuted, I wouldn't say anything that isn't a reply to a new message. But they still take up sidebar space, because it's less convenient to put them in a folder + always collapse/uncollapse them, vs just scrolling past them.

I'd extend this to channels, too. Not muting channels entirely, but just an option (even if it's the same as the server option) that would make them disappear as long as they didn't have a new message. Make the option easily toggleable as a global thing, so you can just toggle it when you wanna add something new to a channel, vs just replying to something or whatever.