There should be an internal way to reset the game with all the existing players. In the same room, or a new room.
Joystick positioning (auto)
something they do in Brawl Stars (the game in the screen) is that if you are anywhere on the left half of the screen it will use the joystick from where you put your thumb (maybe give it a try to understand) and same for the right half.
Implement a .ExitRoom() feature (Unity)
.ExitRoom() will "simulate" the player quitting, like for instance closing the browser or refreshing; Use Case - I was thinking about a game that starts with his own Main Screen, Settings, maybe a Tutorial or SinglePlayer/StoryMode and so on. Then, when the player wants to start a Multiplayer Match, .InsertCoin() can be called to create/join a room. To handle the player abandon the match (not quitting the entire game) maybe to go back to the Main Menu, the .ExitRoom() will be called. If the player wants to join multiplayer later (possibly in a different room), the .InsertCoin() method can be called again in the same "session".