This is an odd one: physical fights between characters or large-scale battles, the first one is the one I struggle with much more. Despite my love for martial arts movies and combat sports, I don't really enjoy writing the fight scene itself as much as I do when writing the reasons behind it. I mean, there's only so many ways to describe punches, kicks, blocks, and basically every offensive and defensive move that is used in a fight. When weapons are added in, my writing is made a bit more coherent and less choppy. On the flip side, hand-to-hand scenes always sound off to me, especially because I'm an avid fighter (on the streets and for sport) IRL. Usually, I feel that reading the scene I wrote actually takes much longer than the fight would in real life. Even if it was extended for dramatic effect (like in a martial arts movie), the scene on paper will have to be much longer to accommodate for the extension. I prefer to gloss over trivial brawls in my stories, but when I write military science fiction (a genre where physical conflict is kind of a requirement), I am forced to do my best.
In terms of writing, large-scale battles can either be easy beyond belief or hard as a pedophile's cock in an elementary school. They also can flow as smoothly as a river or sound as forced as that pedophile raping a child. I usually struggle with large battles when I'm writing in the first person and I feel that a battle is written better from an omniscient point of view. When in the third-person omniscient point of view, battles are definitely easier than fight scenes, but describing the entire event in detail is sometimes challenging. There are so many factors that go into a battle between two armies, and before anyone asks, no firepower and manpower don't win every war. I might not be some armchair general, but just by reading about military history and contemporary conflicts, I can safely say that there's more to a victory than just having more resources than the enemy. Depending on the importance, a battle can be from half a chapter long to half of the whole story. I prefer to keep battles long in the fictional world, but somewhat quick to read. At the same time, I'm forced to also include all the aforementioned details of an armed conflict I spoke about. These two preferences contradict each other, and finding a balance is usually the main point of struggle.