So I CAN follow @startrek on my Mastodon feed but I am not sure how sustainable this will be in one feed when I really start finding interesting communities.

Kbin. What you want is kbin.

I think there will be some pain points crossing between Lemmy and Mastodon. The microblog feed is kind of a firehose when you follow a lot of accounts.

@ragnell @startrek exactly this. It's already borderline unmanageable on the mobile Mastodon UI with just one community.

Well, things should improve a bit with one thing that's being added soon to Mastodon, exclusive lists, where you follow accounts that don't appear on your main feed. https://mastodon.mel.social/@isaacsu/110547014876346015

I kinda wish there was a way to, say, use a mastodon account from another server on here.

Say, you could have a page on here, probably on the login page, where you can tell it "I want to use an account on another server", it redirects you to the other server which asks if you want to give permission, and you click yeah and then you're logged in on startrek.website using a mastodon account or whatever. Would be kinda cool, but it would need to be implemented properly and securely, which I am not capable of.

It probably isn't that sustainable, especially when the community starts kicking off. It might start clogging up your feed, since Mastodon treats each post as a new thread, along with each reply and everything else.

Seems like all ActivityPub platforms will need to be modified with a clean way of handling it if they're all going to live on the same network.