Tape drives will be expensive and likely beyond overkill for this. I’d recommend you grab a blue ray DVD writer and use that instead. The discs are generally shelf stable for 25 years and hold about 50-128GB depending on the disc. Duplicates are cheap, storage is relatively easy, and it doesn’t require constant upkeep/power like a hard drive would. Downsides? They just stopped making the discs, so they’ll grow in cost over time. That’s about it that I can think of.