The power scaling in Dragon Ball Super has always been a major issue, and for proof, look no further than the accomplishments of the Saiyans of Universe Six, Caulifla, Kale, and Cabba. The young warriors effortlessly achieve Super Saiyan transformations on a whim and manage to hold their own in battles in which they should have stood no chance. The Tournament of Power showcased the power of all Saiyans, and even though Universe Seven's emerged triumphant, Universe Six's Saiyans displayed power that defied logic.
Universe Six Saiyans don't know the meaning of the term "power levels," considering that Goku needed to break out Super Saiyan God in order to fight Caulifla and Kale, who were each using Super Saiyan 2. Once they Fused, the newly formed Kefla used Super Saiyan 2 to easily overpower Goku's Super Saiyan Blue Kaioken. It seems like simple Dragon Ball logic that no Super Saiyan 2, Fused or not, should last longer than the time it takes to be knocked unconscious against Super Saiyan Blue, yet the Universe Six Saiyans proved that the series' logic is theirs to control.
The Universe Six Saiyans have been breaking the rules since their introduction. While Goku, Vegeta, Gohan, and Future Trunks all needed moments of desperation and rage to become Super Saiyan for the first time, Caulifla and Kale do it by just powering up while focusing on a tingling sensation in their backs. Yet, the series never gives any indication as to why the Universe Six Saiyans can transform so easily.
The Universe Six Saiyans are all far younger and less experienced than Goku and Vegeta, making their power all the more frustrating. Not only do they reach levels of power that took Goku and Vegeta years of blood and sweat to achieve, but their strength in the same forms completely outclasses the strength of Universe Seven's Saiyans in those same forms. Given the sheer absurdity of it otherwise, there can be only one possible explanation: Universe Six Saiyans are stronger.
Goku and Vegeta haven't always achieved new transformations in the heat of battle. They've each reached new power by simply training, but unlike Universe Six Saiyans, they have never willed themselves into new transformations the moment they learned of them. That the Universe Six Saiyans can transform into Super Saiyans for the first time simply because they want to makes it hard to dispute that they are stronger. The only possible explanation as to why the Universe Six Saiyans are so much stronger is that they are born without tails. Goku's and Vegeta's immense leaps in power didn’t occur until after they'd lost their tails, so there may be a reason to believe that tails are limiting in some way.
The idea that Universe Six Saiyans have more innate power and potential for growth than Universe Seven Saiyans is the only thing that makes sense. If it weren't for their age and experience giving them a head start, Goku and Vegeta would likely not stand a chance against them. The two Universe Seven Saiyans are happy to act as mentors to their Universe Six counterparts, so it's not outside the realm of possibility that they may one day teach the younger Saiyans to wield the power of gods. Based on the evidence so far in the series, if Caulifla and Goku were to battle while each using Super Saiyan Blue, there is strong reason to believe that Caulifla would win.
The Universe Six Saiyans were certainly standouts during the Tournament of Power. After all, Goku needed to use Ultra Instinct, the power of Angels, to defeat Kefla, who was a mere Super Saiyan 2. Should the Universe Six Saiyans ever return to the series, hopefully, it will be in the form of an all-out-for-bragging-rights grudge match with Universe Seven Saiyans. Goku, in particular, has a score to settle with Caulifla and Kefla.