Tbh I read all of this today, and contrary to popular opinion, I didn't see too many things in this fight that hadn't been telegraphed in the writing somehow. I think the reason so many got that impression is because of the fact that this is an adaptation of a LN, so I assume the hints of later developments got more fleshed out there, while in the manga we would get a bunch of short blink-and-you-miss-it hints several chapters before
It feels like the author is trying to be one of those people who are like IT WAS ALL PLANNED FROM THE BEGINNING ahh type but its soo poorly made that it feels like they just making up stuff so that the hero can win