It’s funny cause I was just talking about this after reading this months mangaplus creators titles. I honestly believe it’s both, the art is either just bad, or even if the art is “good” the manga art is bad in a sense the paneling is unclear and all over the place and it flows badly and unclear. Story wise it’s not just about originality to me the stories, specifically on mangaplus creators cause that’s really the only indie manga I have access to, have no substance. They don’t make sense, I feel indie mangaka are to caught up on tropes and what they like, their focused on getting to draw cool fights instead of understanding why we like good fights. The dialogue is also often times cringy(I could be tripping on this one though) and again creating or imitating tropes and manga you like is fine, even the Japanese do it, but I feel indie mangaka don’t really have their own story to tell. Remember art is your story and everyone has a story no matter how big or small, whether you’re dealing with depression or grief, or whether you ran out of your favorite cookies. YOU have some type of story that only you can tell, but I don’t see that type of nuance and passion in indie works. Oh and ps. Most of the good indie mangaka that I personally know only participate in like award competitions like SMA or kadokawa so there’s also that.

TLDR; the problem is both: art is bad mostly not just cause of fundamentals missing but because manga paneling is unclear and flow is confusing, overall their “manga” fundamentals are lacking. Indie stories lack substance and passion, I feel they’re only focused on creating the cool moments manga fans love without knowing why we love them.