A couple of notes for you that should help with superimposing your artwork. (using Photoshop)
• Bring in your artwork from Illustrator / Affinity Designer, you can then use Edit/Distort to match your perfect square/rectangle to the photographed card. Just use the small corner squares that become active, to adjust the edges a little to bring it in line with the photographed card. The photographed card invariably wouldn't be an absolute perfect square or rectangle.
• Secondly although the aim is to make the photograph as sharp as possible, in particular the artwork. It’s not possible to get them as sharp as digital artwork. Sometimes when you superimpose the artwork in it can look a little artificial due to being too sharp. So its often worth trying to blur it a little. I do only mean a very small amount, maybe even just using one instance of Filter/Blur or Blur more would be enough just to take the edge of it.
• As the light will differ across the front of the card, and there is a generally a texture present, after creating your new layer with the digital artwork on, change the layer compositing mode to Multiply. There are others but I generally find that most of the time that is the best one. So change it from Normal to Multiply