I’ve had similar issues too. Aside from Pistol Squats, pull ups have been the only workout that I couldn’t figure out. Until the day I could. I used to get winded after one full pull up. Right now I can do 10 but the last rep is a little sloppy. What I do for my routine is 2×8 pull ups with a 5 minute rest between. Then I do a third set until failure. I also still do Australian pull ups. My personal advice is to just keep doing as many as you can. Once you get your basics down (grip, packed shoulders, no swinging, etc.) Just do what you can, eventually you’ll be able to do more.
Every time I get discouraged I just remember when I couldn’t do two. If I can improve from two, I can improve from 8. You’ll get it.