I’ve half toned this elephant for DTF to go on a black shirt. So when I pasted in vector as a smart object, I expected my PNG to be clean, but instead it made semi transparent pixels around the edges. So instead, place your PNG inside illustrator, then add your vector text. Now to export, hide the black layer, export as PNG and make sure the anti aliasing is set to none. Now if you open it in Photoshop, there are no semi transparent pixels.