If there is an tie, you do it again. If its the same results get an automatic voter thing online and that can decide, if nobody on the server votes, just keep doing it until they vote.
I think what you should do is pick a game mode such as Team Death Match(for example), then maybe rename it to something like “Classic”, and then pick that as the default game mode to pick if nobody voted. You could also pick a random game mode, too.
I don’t believe that would be the best idea, since this could be abused. Abusive players would stall the server, just by not voting, and the intermission is already long enough. I wouldn’t see it as the best ux for players to wait minutes just to play a round
have it select the options in order
[1]>[2]>[3]
if options 2 and 3 both get the same amount of votes it selects 2
if no one votes it defaults to option 1