The writing in DB after the Cell Games sucks, but to be fair, a lot of authors probably don't expect a series to last beyond a certain point. Once they realize "Oh shyt, people actually like this and the publishers want more, I thought it'd be a wrap after 80 chapters
" then the have to deviate from their planned story and planned ending,and start padding and stretching while incorporating ideas that the publisher and the audience want. Even then I sure some people get into the game are like "fukk it, I'll improv after this point and figure the end out later
" I'm convinced a series like Naruto was just ass pulls with a vague outline after a 100 and something chapters in( they probably started planning shyt again for a bit after the time skip, but you cant tell me they planned something like a zombie ninja war from the beginning
).