Library/archive/historical-preservation people these days, for a while now, generally don't use "scanners" to digitize historical printed/2D material images, but ordinary high-quality digital cameras, set on tripods, often downward-facing, and manual page-turning.
There is various plans for DIY rigs for such on the internet, for instance here: https://www.diybookscanner.org/.
(although that site seems to be unmaintained with many broken links, it has enough working links you should be able to get the idea. This was a much more popular hobbyist DIY thing a decade+ ago, in the era of dawn of google books etc).
I wonder if there were particular reasons OP went with a "scanner". it seems a lot of the challenge was finding an affordable scanner that could handle the material. Perhaps it ends up being much (much) faster per-page, especially if you are willing to destroy the original, and is so justified? (Even though they ended up having to do manual page feed, possibly still much faster?) Or if they just didn't think of camera-tripod-manually-turned-pages and know it was a (common) option? If it hasn't been considered, it might be worth considering, although the process they have seems to be working well -- the sample output is stunning!