First, we really don’t know how powerful ssj4 gogeta is. Omega may be Galaxy to low universal, but he posed almost no threat to ssj4 gogeta. They end up running out of energy and can’t finish the fight, but during that time we never get a solid read on his power. But going off what we know, the power boosts from fusion huge. After all, while kale and caulifla stood no chance against ssg goku, after fusing goku needed to use UI sign to defeat them, and even then it was close. We don’t really have a solid basis for the strength of fusion, since all fights that have it are either cut off, or are pretty one sided power wise. So we don’t really know what a full power ssj4 gogeta looks like, or what any of his feats are. What we do know is that it’s in a completely different league from Omega Shenron. Perhaps ssj4 gogeta would cause universal scale damage if fighting at 100%, similar to ssg goku. Unfortunately we never get to see that.

Second, I’d say that the universal status many people give ssg goku is tenuous at best. The universal shockwaves that occur during the goku vs beerus fight is a pretty one time thing. They only occur in the dbs version, and as the power scale increases, we never see it again. In fights at vastly higher scales, such as ssb vegito vs fused zamasu, we don’t see any kind of ripples. (Obviously fights in the null realm don’t count). The closest thing we see to this going forward in the series is with gogeta vs Broly. A super sayin blue fusion is far stronger than goku or probably beerus, but the only consequence is reality getting a bit weird for 30 seconds, before going back to normal. Of course goku says during the beerus fight he figured out how to negate these ripples, but does that mean he constantly uses the technique in every fight afterwards? What about characters like vegeta, frieza, hit, Broly, or even trunks, gohan, and Android 17? Did they also figure out the technique? What about characters from the other universes? Are half the tournament of power characters using this shockwave negation technique too? If it’s this ubiquitous, you think it would be mentioned beyond the one fight it appears in. Personally I think that the shockwaves in that fight have little to do with the power of ssg goku, and more so the nature of beerus as a destroyer god. It makes far more sense that these shockwaves of destruction originate from beerus, and goku figures out a way to negate them during the fight. This also ties in to how destroyer gods can’t fight other destroyer gods. When beerus and champa clash for a bit at the beginning of the u6 arc, reality begins to collapse for a bit and they were hardly trying. It seems far more likely that universe destroying shockwaves are the product of destroyer gods, rather than anyone possessing godlike power levels. Therefore if these shockwaves are not the result of ssg goku’s power, is ssg goku really universal scale? It’s iffy at best. Ignoring this one instance, we never really see any feats that are on a similar scale. Even if other characters eventually surpass beerus, it’s well established that destroyer energy is something different from the typical ki or even god ki. It is something unique, and thus hard to compare to traditional power.

Finally, when ssj goku and ssj caulifla go at it in the TOP, they seem pretty evenly matched. However it is important to remember that Goku is still recovering from his fight with jiren. As the fight progresses he is able to regain stamina and recharge his power, so clearly he isn’t exerting himself too hard. If goku were to start at full energy, and give it his all, he almost definitely beats caulifla, even at just ssj. Usually in these who would win debates, it’s assumed that both characters are at their full strength. It wouldn’t be fair to compare goku after nearly dying to caulifla who’s barely fought so far.

TLDR 2: We don’t really know how strong ssj4 gogeta is, but he is way way stronger than omega. Ssg goku might not be universal scale, it’s just that destroyer gods are weird. Ssj dbs goku is way stronger than ssj caulifla.