That was Vados making a joke about how fat Champa is.
They're otherwise presented as all being around roughly the same level; Whis says that Belmod is stronger than Beerus, though Beerus objects he lost at arm-wrestling.
The fact they can have those kind of contests at all implies they're either even or close enough that it's not clear who's stronger, which is reinforced by the four way battle that's held before the tournament starts. Considering that Belmod believed that Jiren losing in the tournament was flat-out impossible*, there's a pretty strong indication that Jiren stands far above them.
*: Keeping in mind that his own team fielded a future GoD.
Because that was Jiren three or four instances of powering up below his maximum, before he got another massive power-up from overcoming his trauma. Also while the first statement is ambiguous, the second ("There exists a universe where lives a mortal even a God of Destruction can't defeat.") is not.
"All the GoDs ever." don't matter; it's possible that there's one that's a massive outlier from the others*, but that's irrelevant here. The only one that matters is Beerus, because he's the one Broly is compared to. Whis wouldn't exclude the GoD he's most familiar with from a general statement, we have repeated indication that Beerus isn't an outlier from losing contests against Belmod to being treated as equal to Champa, and Beerus has a recurring routine in Super of getting mad whenever someone is implied to be stronger than him, which he doesn't do with Jiren.
*: But probably not since Beerus is treated as about equal to Champa, close enough to Belmod to have contests with him, and the GoDs of the universes that were exempt from the tournament were all shown to be roughly equal. Additionally all the remaining GoDs rose to bow to Goku when he reached the real Ultra Instinct, indicating that none of them have it, which you'd expect would be the case if one of them was a huge outlier from the others since that's what the angels are training them toward.
Goku is explicitly noted and shown to be getting stronger throughout the tournament.