Dan Da Dan and JJK are completely different types of shows.

JJK’s main selling point is the quality of its combat animation. The fight scenes are really well-executed, so it gets high ratings from people who like that kind of thing. Plot and characters are bog-standard shounen fighter types whose names and backstories I forget half the time because they’re not all that memorable. If you swapped everyone but the MC out with characters from, say, Chainsaw Man, I doubt I would even notice.

Dan Da Dan, on the other hand, is character-driven. The interaction and budding romance between the main characters is the point of the show, and the fighting has so far been subservient to that. It also doesn’t take itself at all seriously, unlike JJK.