Answers online range from “they don’t do much damage against netherite armor” to “use a shield” or “fight them with bow and arrow”. But you don’t start with any of those things and it can take a long time until you obtain them.
I mean right at the beginning, where you haven’t found any iron yet and therefore can’t craft a shield or armor. There legitimately doesn’t seem to be any reliable way to kill them without losing half your health. And they are EVERYWHERE. The only thing I can do is run away and dig a hole or pillar into the sky and wait until dawn, and if it’s raining even that doesn’t work.
I have no problems fighting zombies or spiders or creepers. But skeletons are like 1000x harder. What gives?
Caves are guaranteed to have skeletons. Lots of them. So this is completely unhelpful. Sounds like tunneling underground and strip mining for that iron is the only real option here, which can take a long time.