Beerus held off the other GoD's for literally a few pages and even then got caught by Mosco and then it turned into a free-for-all whenever Belmod turned against them, and even after it turned into a free-for-all Beerus came out damaged and he fought Gods individually, he didn't hold his own, if they all fought Beerus together at the same time he would've got wiped and even in this fight Goku states Beerus isn't hold back. Goku does know his power ceiling he was thereand has felt Beerus true power, proof me wrong that he doesn't.