film isn't science exactly but it can be understood better than flattening it to matters of taste.

True but I think debates over what is and isn't too long are more subjective. I've made the point elsewhere, but there plenty of narratives movies as long or longer than this video that are very good, and if anything it's harder to make a good long narrative film cuz there's less good points to pause if you need to take a wiz or grab a beer.

If you think it would be better broken into a multi part series fine, I just don't agree with the idea that long form is inherently bad. If you want to argue the length is detrimental in conjunction with other flaws, like poor pacing and structure, that'd be fine.