I am 6’4" and I had similar problems starting out. I would try for a few weeks, get frustrated and stop, then go back. What I discovered was that I only got better at deadlifting when I was trying to deadlift (big surprise!)
You are probably really weak off the floor, because it’s hard for you to get into position. USE LIGHT WEIGHT for full DLs. Don’t try to up the weight too fast.
You are probably quite a bit stronger at the top half of the movement. Try RDLs: some days with the bar and some with DBs. Just go as low as you can while keeping your lower back flat. Over time, you’ll be able to go deeper.
Single leg DB DLs are good, too. Start from the top, and just go as low as you can without rounding your low back.
I also think bulgarians, with an emphasis on going as deep as you can (try to touch your back knee to the ground) would be a good thing to try.