I don't think there is much of a debate to be had here, Goku almost always had the jump on Vegeta in terms of strength and transformations. It's happened numerous times over the course of the series, Goku is pretty much always ahead of him and once he manages to catch up and they appear to be equal for a bit there is a new transformation or technique that gives Goku the edge over him again forcing him to grow more and again to catch up.
The one time Goku was definitely below Vegeta, if not for the Kaioken Technique, was when the latter and Nappa showed up to invade and take over the Earth in early DBZ. Goku had to rely on his Kaioken to match Vegeta's strength at the time and even then barely managed to win if not for Gohan and Krillin showing up. After that, when we began to close in on the Namek Saga and Frieza, is when Goku started to overtake him. Gravity Training raised his power far above Vegeta's and once the Saga neared its end Goku achieved the Super Saiyan Transformation.
If not for the existence of 7-3 in this Arc then Vegeta would've indeed succeeded to defeat Moro,not because he was stronger than his adversary but because his technique was a straight counter to said adversaries key power/s. Goku on the other hand wanted to rely on Ultra Instinct since it would boost his strength, his reflexes and speed which would be perfect to avoid the Energy Absorption of Moro. Which,if not for Moro's immense power would've worked even, with Sign at that. Or at least that was Merus original plan when he began to train Goku in the Time Chamber.
Vegeta simply had a technical advantage. Strengthwise, he is pitiful.
Pretty sure by now Goku has to power down to match Vegeta before they are doing a fusion dance. As sad as that sounds.
It's a shame that the Janemba Movie wasn't canon,otherwise i had said that he had to before back when they first fused into Super Saiyan Gogeta.