For years, I've played on an IPad and have never noticed a difference. Dots seem fine to me.
Still, I tried changing iPad display zoom setting (from default to larger text). I didn't notice a difference. I also looked at putting grid and dots on my iPhone. Again, I don't see a difficulty in seeing/reading dots.
Below is a screencast of a putting green using my iPhone. Reason I didn't record on my iPad is it's a Pro with 12.9 inch screen. I thought maybe larger screen might make a difference. For me, it really doesn't. While dots are not overly large, they seem fine to me on both iPhone and iPad.
And, as an aside, I don't have the greatest eyesight anymore.