After a Steal/Steal Final Showdown, after all the other players not involved in the showdown get their gold card from the deck, what happens in the event 3 or more players have enough points to win and all of them are tied? I would guess the simplest thing to do is play another complete round, but the rules aren't 100% clear on this.
That is a good catch. There are certainly rules for what happens in the event that players tie for the same amount of gold in a Final Showdown, assuming they were involved in the showdown (you conduct another showdown until there is a winner) but this is a possible outcome (however unlikely) that was not addressed.
If two players have tied for the most gold in your scenario, conduct another Final Showdown between them until a winner is determined.
If three or more players tied in your scenario, conduct another round until a winner emerges.
Thanks for asking!