Do you use a vector graphics app like Inkscape or Illustrator to create your artwork? Vector produces sharp lines and crisp edges that can be scalled to any size. That's not possible with pixel-based rasters.
When I look at these, the first thing to comes to mind is that they should be vectors instead of jpeg photos. I believe many of the technical issues are from the file type that is used.
There could be others, but when zoomed in the details are too pixelated to tell for sure.
The building background of art-03 seemed out of place to me compared to the illustration.
Overall better for sure. If you zoom in on the eyes, there is a lot of pixelation in them, and in various places throughout the photo. There is also substantial moire in the background.
Are these renders? Or digitally hand drawn illustrations?