You can use Photoshop, Affinity Photo, Gimp or any other 2D application to layer multiple images. (Look for layer blending modes.)
However you could achieve higher perceived resolution by layering the textures in an Unreal material. For example wall dirt, repeating wall paper, up close mold, each at a different scale. In that case the “multiply”, “add” and “linear interpolation (lerp)” nodes are commonly used.