It's a bit hard to say for sure. Both Vegeta and Goku have their moments of strength. Goku has some unique powers and techniques that give him an edge at times, but Vegeta is no slouch either and constantly works to catch up and surpass Goku.
Generally, Goku still holds the edge over Vegeta. Their power levels fluctuate, but Goku often achieves higher peaks of strength and unlocks more powerful forms first.
One possible analysis could be that it often explores the dynamic between two powerful and complex characters. Goku Black, with his menacing and somewhat twisted nature, and Vegeta, the proud Saiyan prince. In fanfics, their interactions can range from intense battles to unexpected alliances. Maybe it delves into how Vegeta would react to Goku Black's presence, given their different ideologies and power levels.
A possible fanfiction could focus on a group of Saiyans who are trapped in a dimension where they can only watch the Goku vs Frieza fight on repeat. They start to notice small details in the fight that they hadn't before, like the exact moment Goku's power level spikes or how Frieza is trying to adapt his strategy. This newfound knowledge could then be used by them in some way when they eventually break free from that dimension.
Trunks would also be interested. He has his own experiences with fighting powerful foes and would be eager to see how Goku, a great Saiyan warrior, fares against Frieza. Also, the younger Saiyans like Goten might be interested. They've heard stories about Frieza and would be excited to see their father or other Saiyan heroes in action against such a notorious villain.