I'm a big Bleach fan, but come on. Ichigo lived off one move the entire manga, Getsuga Tenshou. He branched out only when his Hollow side was involved. This just seems to be more so of a Shonen thing with main characters.
Ichigo doesn't fight stupidly though. He's just completely uncreative with his moveset which makes him more of an outlier.
Luffy and Naruto are creative when they fight for instance.
It's really interesting how little super genius protags there are in battle shonen. The closest thing to the strategy you get in a Jojo battle is... maybe a sports shonen? The strategic elements, counterplay and teamwork (along with fantastical powers depending on the shonen) are kind of similar.
Writing a super-genius as a main character is much harder than writing an idiot main character. The more competent a main character is, the harder he is to write.