Aren't there "street smarts" feats that justify that?

Like Goku himself, he's often refered as being a genius as long as the topic in question is fighting. Even when shown new techniques, he'll quickly figure out its weaknesses and tear them apart, and even call out on "uncreative attacks".

I think the Cell fight was the last time he would show how skill and expertise can take out superior power level and IQ, Cell being "book smarts" from Gero's computer and Goku "street smart" from, in TFS terms, eating many horses. Not sure if a dub addition but I think Cell admitted Goku would have beaten him weren't for the Android Barrier.

Also, dat sweet ass double quadruple reverse flip kick to Cell's perfect chin.

Minmaxed STR/CON/INT virgin bug man vs balanced chad with high DEX/WIS/CHA, epic feats and mentoring from the greatest masters acquired through adventures, not starting backstory.

I always say things like that as a joke. my favorite is
"Now I'm not the sharpest Lighbulb in the crayon box"