I would've just made it like the manga, the anime made it dumb. And I'm not even referring to the Frieza/Goku team up against Jiren, because until I read the other posts I honestly forgot about that. For whatever reason, I thought the manga adapted the ending sequence between Frieza, Goku, & Jiren but I youtube'd it and yep, you guys are right. The problem for me isn't so much that it's out of character, but that there's no interesting finish in the anime. Like, the finishing blows are one thing Dragon Ball has always made iconic memorable moments, like the father-son Kamehameha or Goku's defeat of King Piccolo, but there's no memorable action set-piece here, the only thing selling the ending is the sight of Goku & Frieza fighting together. In the manga, they actually set-up a memorable finishing sequence that even features some strong callbacks.
But no, my problem has to do with how they handled 17 winning, the anime messed it up in ways I didn't even know was possible. 17 winning was one of my favourite parts of the manga, especially as since 17's always been one of my favourite characters. Here's the two ways Toei's version is infinitely inferior.
I. It was no longer a plan. In the manga, 17 "blows" himself up in an attempt to eliminated Jiren, has this goodbye speech to Krillin & 18 and everything. But of course, this was all a ruse, a plot he devised with Frieza in order to win. In the anime, 17 sacrifices himself to shield Goku & Vegeta from Jiren's blasts. And when he's revealed alive, he claims he just got lucky, since it was a gamble if he'd survive. So in the manga, 17's sacrifice and re-appearance is brilliant strategy of subterfuge, highlighting tactics instead of brawn power, which works well considering the circumstance. In the anime, it's just a decision 17 makes in the moment and it barely accomplishes anything. In the manga, 17 was the integral player to winning the ToP, and the anime, 17 was just the guy who didn't get eliminated.
II. They revealed 17 was alive before Goku, Jiren, & Frieza were eliminated. This decision baffles me. In the manga, 17 doesn't reveal himself until everyone's been eliminated, part of his plan, but it also just makes the elimination dramatically interesting. Like, the audience also doesn't know what's up, because as far as we know everyone's been eliminated. 17's a nice surprising twist at the end. In the anime 17's chilling while Frieza & Goku eliminate Jiren & themselves. There's no intrigue or twist, it's just a straight boring moment of victory. And again as a 17 fan, it means that 17's role in the finale was just the guy who's left.