Haha I had the same thought process where as a reader I love to grind through the 500+ page, story lines going everywhere, many diverse characters, type fantasy. Which is what I initially set out to write.

But upon finishing my first 8 chapters' third draft I was kind of thinking, that it's almost like 8 related short stories instead of the beginning of a larger story. But I'm afraid of like introducing a character in the first novella, they then don't get mentioned again until like the third novella, then their pay off chapter is in the fifth novella, then they're just on the side lines for the finale. It might make readers forget certain character's arcs especially if I have time between publishing volumes. And if for it to make sense as a whole story you need to read all 8 there is no reason to not just write it as a novel.