Like the way its structured to start with is the extremely tight view that drives home that all these other characters have their own lives and existence but you only ever the few bits when Frieren's around and then they're gone, while the pacing keeps up this constant feeling of time slipping inexorably away and being lost forever. It hits hard and is structured perfectly for those themes.
Then it hits a point where the story shatters into a bunch of separate threads and grinds to a complete halt in the way that stories that split into a bunch of threads inevitably do. It loses the tight focus and the feeling of "yes, these characters have their own existence but you only interact that during the moments you're actually there" sort of thing in favor of just showing you a blow by blow of everything that's going on with them, and instead of time slipping away no matter how hard you hold onto it it instead stands completely still.
It stops being unique and impactful and starts being "that annoying thing from BNHA where they spend like half an entire season going into excruciating detail about some little training exercise with mild competitive elements that every single member of a huge cast is participating in" instead.
Given the rest of the what we see of character who claimed that's arc I can't help but wonder if he wasn't just bullshitting or doing something like misrepresenting a desperate village continuing to fight after losing most of its adult male population as some galaxy brain human shields nonsense to turn the blame away from himself and onto others.
It really felt like it was trying to channel Hunter x Hunter and BNHA there. It also felt like it was trying to backtrack a bit on the cutthroat brutality stuff, cause even in the first trial it backed off and was like "wait no actually most of them were bluffing and are actually uncomfortable with the idea of just casually murdering each other for status, but they want to intimidate the others into backing down so they play psycho" for most of them except Ubel.
For what it was it wasn't terrible, but it really did ruin the feel the first bit had. Like Frieren being this horrifyingly powerful bag of repressed trauma whose whole life has been some weird deep cover sleeper agent shit is entertaining, and I honestly think the show could have ridden a lot more on the having her give up on subtlety and just casually murk some horribly threat before continuing on with something silly and trivial bit a lot more, like its slowly revealing that it's just One Punch Man, but Elf. That was a funny enough gag and they could have gotten way more mileage out of it than they did before miring themselves in the snails-pace blow-by-blow shonen fight scenes.
Yeah. It doesn't hit as hard as early Frieren, which actually brought me to tears repeatedly because the whole "endless churn of people you may never see again as time slips inexorably away" shit strikes a nerve hard, but it is overall the better work.