alt Hacker NewsHonestly: multiple copies of encrypted cloud storage. (Encryption just for privacy.) You need decentralized backups anyway. Alternatively, two NAS systems with some RAID variation in different locations that back up each other can be more cost-effective for large capacities.
You're talking about backups which you wouldn't normally need to keep for decades and will be powered on regularly anyway. If it's archival, such as family photos for your kids when they grow up, cloud storage can lose them if you die or go to prison or for whatever reason don't keep paying the bill.