The standard that they came up with is called "Archival Disc" (AD) [1] and they fulfill the requirements of 100 years (lab tested and verified) data retention. The ODA units, however, cost over 8500$ last time I checked.
As far as I know you can order them from the Panasonic Japan website and not anywhere outside Japan, but this standard has huge potential in my opinion (when compared to the absurdly overpromised mdisc, for example).
Data retention rates matter, always have an optical and a spinning HDD backup. SSDs are not guaranteed to keep data longer than 30-90 days without electricity.
SSD retention claims vary depending on the drive; and it's a trade-off between speed, durability, total writes, etc.
At reasonable room temperatures, powered-off SSDs will keep data for years.
Losing a single bit is unacceptable for archival purposes, that's why I mentioned the importance of optical and magnetic backups as a redundancy.
Sure you can probably correct file headers, but that's it. Anything that's relying on file integrity probably will go nowhere without a redundant backup to correct the data from.
I'm not talking about "good enough" == "some pixels are wrong in a jpeg file". I am talking about legally relevant documents where authenticity matters and a single bit flip might cause the court to not accept the documents as evidence.
You need to spread the files (including the redundancy codes) over enough disks that you expect to be able to access sufficient blocks in the future.