I’ve often remarked that one of the last scenes I will write in a novel is the ‘climax’ fight scene, or any other fight scene. I’m afraid I find fight scenes boring.
Every sentence in a novel or short story exists to either further the plot or show character, or ideally, both. Fight scenes don’t do any of that. Fight scenes are blow-by blow accounts of what happened. Unless their interest is in sword-fighting or war strategy, most readers won’t find them all that interesting.
Think of it: we get to the end of the novel, and your protagonist finally meets the antagonist face-to-face. We know there’s going to be a fight. They know there’s going to be a fight. We know that one of them will win. We know that the closer the scene is to the end of the book, the more likely it is that the winner is the protagonist. In any case: someone will win. We want to know who, and not be taken through three pages of backhanded cuts or army manoeuvres. Fight scenes are procedurals and long procedurals are boring.
You can make them interesting by adding a different angle. For example, the protagonist isn’t aware who they are fighting, and much of the fight is spent trying to find out. Or the antagonist drops an emotionally-laden comment during the fight (Darth Vader: I’m your father), or something unexpected happens (the elves turn up in the battle of Helm’s Deep). But there are a lot of fight scenes where something like this simply isn’t possible, plot-wise. Just keep them as short as you think you can get away with.