If you want longevity and shelf stability, tape drives are the way to go. You can get them in very large capacities, even into the hundreds of TB.
Their benefit is that they have no internal motorized components, they are a lot like VHS videocassettes - two spools with tape. This makes them very shelf-stable, unlike hard drives which can have their spindles seize up over time.
They also have absolutely epic data densities. You could store on one tape the contents of dozens of the largest hard drives currently available.
Their downside is that you need highly specialized hardware to read and record them. And this makes the hardware quite expensive.
So why don’t we use tape drives to store data? Because they store said data linearly - great for writing once, terrible for finding or updating said data - and because they are slow. You want to get to a file 20Tb in? Enjoy scrolling past every single byte up until that point.