Getting DVD's to look good on new equipment.

So, I have been buying a lot of DVD series lately and noticed I. The Past too that they look awful played on my Bluray players and 4k TV's. Up close they look horrible and there's tons of artifacts and everything has like an outline around it. Is there any way to get these to look better? Blurays played through them look great. And yes, I know neither DVD's or Blurays are 4k. I recently bought MASH, Curb Your Enthusiasm, Doctor Who and more and they all have these problems as have all the DVD's I've bought over the years.