There was an episode of the podcast 99% invisible about the facility mentioned in the OP. It concludes with the idea that the best way for ideas and messages to survive for thousands of years (and transcend language barriers etc.) is to engrave it in the culture of the people at the time. A great example, and one used by the podcast, is to create genetically engineered cats whose eyes glow in the presence of radioactive waste, and to then create culture about this idea. For example, a song / nursery rhyme that impresses the idea that when a cats eyes glow, you aren't safe. [1]

[0] https://99percentinvisible.org/episode/ten-thousand-years/ [1] https://www.youtube.com/watch?v=g78hZIEqONM