That's how it is unfortunately. The best way to get people on Matrix would be by communities hosting on Matrix and advertising that actively in their Discord guilds. Providing simple instructions to pick a client and sign up. Show people they can customise how they like etc, that will help, people love shiny things. Once you have people signed up and using the platform, then they can figure out the federation by being exposed to it.
warm
Matrix is better in all these regards yes, but Revolt has one major upperhand. Onboarding simplicity. A big reason the fediverse has struggled to gain major traction.
If you have to read documentation to understand how to sign up to something, then that's immediately enough friction to turn users away. Bluesky worked because it was simple sign-up, Mastodon has switched to this too now, offering a button to send people immediately to a signup page on their default server. For major adoption, you have to get people in the door before you explain federation, not the other way around. Sending people to list of servers and clients they can use is bad user experience for the masses.
Revolt will appeal to Discord users more than Matrix, because you download Revolt and sign up to Revolt, there's no extra thought required.
It's cool, but the problem is the scale, how is Revolt going to fund the server costs if people ever started migrating from Discord? Just purely donations?
International law couldnt give a fuck about that. That's like saying Russia could legally invade Ukraine if they have a law saying it's okay.
Okay, then people can download whatever they want, maybe they are making their own ai too.
I had the same experience, I think the simplest way is to just have servers separated like they are now in Discord, and you can join them and chat in them even if you signed up at a different server.