Having played Halo CE for PC recently…no, it doesn’t have split screen at all. That was only on the Xbox version (which is technically superior in quite a few ways). The only way to have split screen on Halo CE on PC is via console commands/mods. That said, I do agree with your overall point and I would love to be able to do split screen MCC on my PC without mods.

It’s the cost of federation with instances that try to be giant general-purpose instances (.world and .ee, mostly): just constant shitty takes that overwhelm participants in the conversation. Federation works far better with lots of small purpose-driven instances instead of gigantic ones; my small (<1000 users) specific community-focused Mastodon instance sees absolutely nothing like this and is full of people who intentionally engage in good-faith conversation with the rest of the community while every large instance I’ve seen has the same issues as centralized social media in that regard.

Is there another alternative? Bandcamp is the only similar website that a lot of artists I enjoy use.

If you’re watching movies with friends and want a FOSS alternative, Jellyfin is the way to go. It’s basically a way to host a media streaming center that others can connect to. It might be a bit overkill depending on your needs, but it’s great for that exact purpose. It doesn’t have chat or anything, though, so you’ll want to keep something else around for that.