Your mileage may vary, as it’s a project that doesn’t look to be actively worked on anymore, but selfhosted-gateway is a simple wireguard docker setup that’s relatively easy to set up. It spins up the relevant proxies and tunnel, Doesn’t cost anything, nor is there any signups etc… all you need is a VPS, a domain name and a home machine.

I wonder if this is behind the inspiration for monster hunters murder pickle, aka Deviljho.

I think this would be a new California republic… Which coincidentally also has a flag

Matrix is an interoperability protocol (like activityPub, which mastodon, friendica, Lemmy, pixelfed etc… all use to communicate with one another) rather than the actual application being used.

The UI you’re describing is probably Element, which is the most common matrix implementation used, though others do exist. A good example is probably rocket.chat; they’ve leaned harder into the discord like feel, whilst making use of the matrix protocol.

As for Stoat chat; It’s a rebrand of revolt chat, who have previously resisted calls for federation due to the perceived complexity of implementing (or creating their own i guess) protocol. That’s not to say it doesn’t have it’s uses; but it would be silly to assume people won’t try to steer you towards  federated services on the fediverse 😉 and stoat don’t seem to have changed their stance on the matter.