It's possible you got a fake? There were a couple of reviews saying they went through a similar experience and the only tell was the packaging it came in.

I actually purchased a pilot metropolitan and it worked really well after a few mins of getting the ink to flow through it.

My only gripe is that it has an odd quirk with certain strokes but a lot of reviews mentioned this.

I actually tried this and it didnt work.

I played a lot of similar games and they all have that. I was surprised Diablo didnt. Maybe I disabled it?

I switched to controller recently because of this and not being able to stand in place and attack without moving.

I honestly feel controller is a lot more enjoyable. My only gripe is navigating the inventory but it's such a non issue when your mouse is right there.