While this is dragon ball and I doubt that they will do it, they can run the clock.
That is what 17 would do, and that's why he's very likelly the next one to be KO.
Well, tournament wise:
Goku vs Jackie Chun ended with both extremelly exhausted, and Jackie getting up first, but after the count ended. Goku actually stood up first, but couldn't stay concious.
Goku vs Tien ended in a race to the floor, after a hit on the air, after Tien vaporized the arena, that Goku lost because he hit a car.
Goku vs Picollo, I think that was also a ringout, for a very broad and generous definition of arena.
Vegeta and Toppo are the only ones who have managed to damage the bottom of the arena though, and after Jiren mad platforming skills to recover with just pebbles, I doubt that they could reduce the floor to nothing and succeed.
A KO seems impossible at this point, Jiren (not counting Beerus and Goku Black) seems like the biggest power differencce in a final battle, and without another powerup it seems unlikelly to end in U7 favor. And other than Frieza and Cell, the most emblematic bullshit powerup of the history of manga, Dragon Ball didn't do it that much. Actuallly, Ultra Instinct seems closer to the way that Luffy uses them, a first try that ends just shy of victory, and another go for the KO, but UI just barelly did something.
Spirit bomb failed, Zeno or Whis aren't helping, Jiren is enough of an asshole to diss Toppo after he sacrificed his identity to win so no friendly resolution.
The original idea that I had was that the high priest needed to reduce the number of universes to do his plan, but if it is one more, then he needs the tournament to end, making his intervention or a interruption useless.
Another interruption would also not help U7 as it would happen after the end of the tournament.
MasakoX proposses that as the super dragon balls are either from U6 or U7, they either were eliminated, or are going to be eliminated, rendering the wish impossible, and forcing Zeno to hold or undo their elimination.
We are in the territory of another bullshit powerup, they wise up and run the clock, or they lose and manage to survive out of the skin of their teeth.