I've thought about the "hundreds of years" problem on and off for a while (for some yet to be determined future time capsule project), and I figure that about all we know for sure that will work is:

- engraved/stamped into a material (stone tablets, Edison cylinders, shellac 78s, vinyl, voyager golden record(maybe))

- paper, inked (books) or punched (cards, tape)

- photography; microfiche/microfilm (GitHub Arctic Code Vault), lithography?

I actually looked into what it might take to "print" an archival grade microfilm somewhat recently - there might be a couple options to send out and have one made but 99.99% of all the results are to go the other way, scanning microfilm to make digital copies. This is all at the hobbyist grade cheapness scale mind you, but it seems weird that a pencil drawing I did in 2nd grade has a better chance of lasting a few hundred years than any of my digital stuff.