I’m going to guess cave paintings are going to out last all books and digital media backups.
Not when the earth floods due to climate change.
There are cave paintings/petroglyphs at 3000m above sealevel in the valleys of the Andes, central Asian mountains and Tibet (and probably more I don’t know about). I dont think there is enough water on earth, ice or otherwise for 3km sea level rise.
Do you think there is going to be a Noah-style, waterworld flood? How high do you expect water levels to rise?
You want to store information for eons? Build it in to the ratios of a pyramid. Then no one will ever figure it out. Or at least there will be a huge disagreement as to what you meant.