My father told me he wanted to make USB flash drives of all the scanned and digitized family photos and other assorted letters and mementos. He planned to distribute them to all family members hoping that at least one set would survive. When I explained that they ought to be recipes to new media every N number of years or risk deteriorating or becoming unreadable (like a floppy disk when you have no floppy drive), he was genuinely shocked. He lost interest in the project that he’d thought was so bullet proof.
Hard drives offer the best price/capacity ratio, but they need to be powered periodically (at least once or twice per year). As with any other storage medium, include parity data and have multiple backups to avoid data loss.
Tape is too expensive.
Optical media can also be pretty good as long as you get discs made from inorganic materials and store them properly. M-disc is supposed to last like 100 years. The biggest problem is that they are on the path to obsolescence and optical drives may stop being manufactured. Also, it’s a good idea to check on the condition of the discs periodically and redo any that shows signs of degradation (probably a good idea to replace non-M discs every 10 years regardless).
But regardless of the media, there is no archival method that doesn’t require active maintenance, like periodically checking the data, ensuring you have multiple backups, refreshing any aged media.