I don’t know about your budget, but I’d do it onto HDDs. They’re cheap and large. But use two and regularly check them like every other month or so. If one breaks, get a replacement. That’s the most simple (if you have an external dock) and cheap solution that you OWN.

Also copy it at least twice onto each in case of corruption. Also use a copier that verifies (fastcopy, teracopy etc)