Either Topaz Gigapixel or PhotoAI might help. It all depends on the image. Topaz products can be downloaded and tried before you purchase. That might be the way to go.
I’m curious, when you scan, what are the dimensions and resolution? Perhaps you just need to scan at a higher resolution. Unless of course the images are very small.
The scanner is fairly good; the image is not pixilated by the scanner but shows the print defects.
I have 2 things in mind: 1) scanning a book of black and white prints of geometric patterns
2) scans from books with colour illustrations, line drawings from old engineering catalogues
If you can post a picture of one of your scans we might be able to see if you have used the correct scanner settings. It’s important to get the right settings.