Dragon Ball Super has been steadily upping the game when it comes to the new (and still somewhat mysterious) power of Ultra Instinct. Goku first tapped into the divine ability during the Tournament of Power arc - but that achievement was born of desperation and necessity, as the Saiyan hero needed to surpass all limits to save his universe. Since the ToP, Goku has been studying with angels Whis and Merus to master Ultra Instinct - only to learn he has an entire ladder of power yet to climb.
Now, as Goku and Vegeta's latest battle has begun with the strongest warrior in the universe, it's been revealed that Goku's Ultra Instinct could indeed become stronger than the angels!
Warning: Dragon Ball Super manga SPOILERS Follow!
Goku reached the complete form of Ultra Instinct in order to take down the ancient evil sorcerer Planet-Eater Moro, during the finale of Dragon Ball Super's Moro Arc. However, the new arc, "Granolah The Survivor," has carried things forward yet another step with its serialized continuation of the Moro Arc. Goku has learned from Whis that Ultra Instinct is a state of mind more than it is a full-powered transformation; Goku has learned to achieve the Ultra Instinct state in his normal base form, only manifesting the power-draining complete transformation when drastic situations call for it. However, in Dragon Ball Super chapter 72, as Goku is going all out to battle Granolah (whose power has been boosted to universal heights thanks to a Dragon Ball wish), the Saiyan warrior unveils a new tactic...
While fighting Granolah in Super Saiyan God form, Goku slips into the Ultra Instinct state, combining UI's speed, power, and focus with the boosted power of SSG. It's just a brief moment of combined power (Granolah still is able to get the upper hand with some one-of-a-kind techniques), but it's clearly a roadmap to where Akira Toriyama is taking this new ability.
Dragon Ball Super has always carried the subtext of Saiyans being compared to the strongest powers in the multiverse - mortal and beyond. In fact, as the series progresses through arcs like the Tournament of power, it's become a larger and larger point of debate about just how long the gods of the universe will remain superior to Saiyans, in terms of power.
When it comes to Ultra Instinct, on the one hand Goku seems like he's at a disadvantage to the angels: Granolah is able to beat SSG UI Goku because the Cerealian warrior's enhanced eye can still pinpoint the weaknesses in Goku's physical form; blood flow, muscle movement, pressure points... angels presumably have none of these physical limitations that mortals do. On the other hand, however, the angels have only one mode of transformation we've ever seen: they can access their angelic powers or choose to mask them. In fact, it's Angelic Law that Angels never use their angelic power to fight on the mortal plane - violating that law is what got Merus erased from existence, during his battle with Moro. Whis has made it clear an angel can grow his/her power, as Grand Priest is stronger than Whis, who is in turn stronger than Merus. However, angels have no 'Super Saiyan' transformation that radically boosts their power.
We now know that Goku can apply Ultra Instinct to his Super Saiyan transformations, and that is a game-changer. The more Goku hones and perfects his base form of Ultra Instinct, the more powerful it will become when used with SSJ, SSG, SSB, or anything beyond those transformations. That's an entirely new and unique form of Ultra Instinct the universe has never seen - and the ceiling of that power could likely tower high above what any angel has ever achieved.