https://www.unitex.co.jp/en/products/hardware/lto/lto-tapedrive/
Found from a google, no experience with it.
Tape is not a nice medium for the self-hoster, the drives are expensive, the tapes need to be carefully stored securely (temperature and humidity controled). Its a lot of hassle. That said, if you find something good, I'm interested as well, so report back.
Be a parent, and be present when they are using it. You don't have to watch constantly, but at least be nearby. Teach them basic digital safety, literacy, and privacy skills.
You cant control all the devices they have access to, so you have to give them to knowledge and tools to be safe.