How to use a material instance from Quixel to paint over a landscape that uses a single texture as its material? (UE5)

I currently have landscape that uses a material with a single texture. I want to paint over it using a material instance from quixel that I have edited to have less tiling. If I go into the existing material I can only seem to add other texture samples to a layer blend, not the edited material instance. I have tried to covert the material into an instance to make a material blend but that doesn’t work either because the material is a single texture.

I have searched for an answer for this simple question for a while and cannot find a solution. All the videos seem to start from scratch only using material instances.