It's a lot of up front cost, but a NAS that is RAIDed with parity puts you in a pretty safe spot.
The short explanation is you have at minimum three drives, and you "stripe and span" them. This is a setup called RAID 5 where, if any one of the three drives fails, it can be replaced with a similar-sized drive and the "parity bits" from the other two drives can rebuild the data on the third drive. Yes, this means you only have the effective space of only two out of the three drives. So say you had 3x4TB drives, you'd have a total of 8TB to work with, and one drive is the "parity" drive (although this is actually split among the drives, so if any one fails, it can be revived by the other two).
However, in practice, the space lost is worth it for redundancy. It does mean an up-front cost in buying drives, a NAS enclosure (or using something like TrueNAS plus off the shelf parts to build your own), and includes the cost of physical maintenance and support (a Uninterruptible Power Supply to keep the hardware safe, for instance, on top of eventual maintenance of physical parts).
The offers the cloud solutions seem cheap up-front, but they don't buy you as much time as the one-time up-front cost of building your own NAS and maintaining it. I understand why people choose the cloud solutions, it's much easier. But if you're dedicated to this lifestyle, it's something worth looking into, at the very least.