Here is another option for you.
As I mentioned before I often scan maps, photos and have scanned old very fragile silk maps from world war 2 that some paratroopers had in their pockets to use at night so the silk would not make a noise near the enemy.
Some old maps I scan are so fragile we cannot handle or move around too much or the paper will flake apart. The old way was to hold the map above the scanner and scan in many pieces.This way will damage these maps etc.
You mentioned that your image being damaged by dragging the image across the scanner and destroying the detail. True! This was a problem I had with artwork I was given to scan like pastels etc.
The solution I now use is a canon LIDE 220 flatbed scanner scanning upside down with a handle mounted to the unit so your sketches can stay flat on a table.The scanner is lifted up and down gently without a single smudge.
The scanner will optically scan at 1200 dpi but 300 to 600 for you will be fine, depending on how large you want to reproduce these images. Here is a website you can look at if you want to go this way. It certainly solved these problems.
https://mpetroff.net/2013/09/scanner...rge-documents/
Not all scanners will be able to scan upside down . Also scanning with a flatbed scanner your images scanned will always be straight so saving and tidying up later is easy.
Just a suggestion Alex.
Peter