its impossible for not wifi, cause wifi is internet, and without internet, you cant communicate with other computers, which doesnt allow online multiplayer. although, you can ask poeple nearby in a cafe (for example) to play a local server, which only uses the same internet, although you'll still have chances of disconnecting, and if you don't wanna get disconnected, play freeplay, and if that's boring to you, then just don't play among us.