So I am using an asset (Assetville Town) and I am trying to switch the main roads and ground textures to something a little more realistic. I don’t want to redo the entire level as it uses ONE texture tile for all the colors and roads. What program or what could I do to retexture that tile so that the ground looks more like concrete instead of just a gray color. I’m familiar with just replacing the material, but this one doesn’t work like that. Thanks!
Gimp or photoshop 
You can probably do it by cutting up various more realistic Megascans textures.