

There are plenty of “private” servers that are technically open to anyone. Just follow the rules and enjoy the game.
You’ll see a lot of “B42” or “build 42” being talked about. This is the most recent major update that is still in beta. It doesn’t have multiplayer but does offer A LOT of new and improved features.
B42 is a beta branch like you say, you have to opt in to play it. The current version does do multiplayer, I’m currently running my own server for my friends on the current version