I met similar sensation in the case of Hobbit, where Imdb rating is highly inflated by Tolkien's fans 10 star votes. If you just watch the story, you will find out dozens of side storylines, which make completely no sense. How they pass through goblin barracks - where is the tight atmosphere in that battle? The love between an elf and a dwarf is based on the fact that his dick is big and the stars are blue... Yet it was still watchable.
If I hear the name of James Cameron, I don't even consider watching it. He is the author of Avatar. A film with good effects overall, but main storyline is about how bronze-age civillizations destroys well-armed galactic-travel capable civillization. A story like that can never make sense and can only be about effects and visual work. I can totally understand if Alita is wrong in similar ways...
Just don't take me wrong. A story, which would make no sense in our world can still make for a good movie / book. It just needs to have created a world, where it would make sense. Like in Mortal Engines, where the author totally ignores some laws of physics, but the world seems well fleshed and good.