time gear
Eternity in an hour
The point I'm making is that Goku is very used to fighting people who are very similar to himself. Kirby just copying Goku's powers isn't enough to give him enough of an advantage to win, and since Goku's also a martial arts prodigy he's got more than enough skill to make up for Kirby having a similar powerset.To put it as simple as possible, I'm saying that Goku would often fight even individuals who would be much stronger than him whilst not giving a shit, and yes i am ignoring Kirby being a part of this.