the lobby browser is okay, but its not really ideal for this sort of game.
really, the whole multiplayer system should be accessible from the mission selection map. when you plan to go into a mission, it should ask if you want to host or fill into a multiplayer map, or go in solo/not matchmake if youre in a squad.
think of games like marvel rivals or overwatch. it takes no real effort to find people to play with and just hop into a match.
by making us select a lobby, that might be 90% through a mission or sitting AFK in the saloon, players will get huge decision paralysis and just not play.