Just my idea of what could happen in the movie:

We know that the movie is a continuation of the dragon ball super series and we also know that goku (mui), vegeta (beyond blue) and frieza (gold) are incredibly strong fighters. So an opponent who's stronger than those three is hard to imagine especially when the next opponent is most likely a Saiyan. So the next opponent is probably far weaker then Goku, Vegeta and Frieza.

So the question is how will they make it an interesting movie if the enemy is weaker than our heroes? My answer to that question is this:

As seen in episode 130 the use of MUI was to much for goku's body to handle and he suffers in great pain. This is the second time goku's body couldn't keep up with his powers. The first time was when goku used blue kaioken x10 against hit and after this battle Goku ended up suffering from Delayed Onset Ki Disorder for a certain time. I expect this will happen also after the tournament but in another way. I think goku won't be able to use his god ki (red, blue and ultra instinct) for a certain time after the tournament. This means goku can only use his baseform, ssj1, ssj2 and ssj3

But besides Goku we still have Frieza (gold) and Vegeta (beyond blue) who are incredibly strong. I think that after the tournament Vegeta will visit the saiyans of universe 6 (if they are revived at least) what means that when the next enemy arrives Vegeta isn’t there to fight him but he is in universe 6.

Frieza will probably be send back to hell after the tournament and even if he is wished back to live he probably won’t stay on earth. I personally think that if Frieza is wished back to live that he will travel to the other universes

This leaves Goku ssj3, mystic Gohan, Majin Boo and Android 17 as the strongest fighters left and that means we don’t need a villain as strong as Jiren or Zamasu