What finish could be applied to a wood project with paper on top to seal and preserve the paper without discoloration or damage
Epoxy.

I looked for, but could not find, a link to the special electrical fibre glass- it's aluminum oxide instead of silicon dioxide, made in a finer grid, and is practically transparent when soaked and placed on the surface. It's also used for boats/canoes and shows the would perfectly. It is not, however, 100% optically clear so would obscure fine detail.

If you want perfectly clear you'll want one of those countertop type epoxy, and there are plenty of videos on that out there.