<3

How exactly do you make the Dreamcast/PSO connect to one of these servers?

Typically a raspberry pi running DreamPi

So it's possible to connect to Phantasy Star Online's servers? Presumably they're no longer run by Sega.

There’s a couple of different servers ran by hobbyists. All free of charge (though I’d happily pay).

There’s also servers for the GameCube and Xbox versions of PSO too.

PSO unfortunately didn't have much of an endgame (all you can really do is glorified boss-rush mode), but I still got a couple extra years out of it circa 2007/2008 via the Blue Burst PC port with unofficial English translation. Nostalgia aside for using a genuine Dreamcast controller, Blue Burst brought some nice expansions and QoL additions. To boot, the guys who hosted the servers also brought back some of the "holiday" events and Japan-exclusive stuff that Sega used to host. Being able to run around with some of the staff-only skins (like Sonic/Tails/Knuckles) and a Sega Saturn MAG floating on my shoulder was fun, indeed!

PSO is an MMORPG (in fact first of its kind, at least on a console) so it’s not really about having an end goal but more about guilds going on quests together.

Eh...I think the term "MMORPG" is incorrect. It was clearly in the vein of the original Diablo (and they're not at all shy about admitting this).[0] Even though the lobbies may have been "massive", each local game-room was still capped to 4 players.

[0] https://en.wikipedia.org/wiki/Phantasy_Star_Online#Concept