I found a How-to-Play guide that states "After a round is over, the player who tapped all of their characters first becomes the first player for the next round. You untap all characters and the next round starts with the first player. This continues until one player wins by being the only player with characters on the board."
If this is in fact how the turns work, if I tap Metroplex for an attack and get his ability off, Metroplex will be tapped first, then all my opponents bots will tap letting Metroplex go first next round. Or is it still turn-based as Metroplex taps all opponents bots? Metroplex's players turn ends and then everyone untaps and it is now the opposing players turn?

This is not technically how the rules work. There are no rounds in the Transformers TCG. When your turn is over, it is then your opponents turn. Please see the official rules here for further details.

Source: Wizards of the Coast (2019-04-22)    【Link to Ruling】

Tags: Play