External HDDs: good option, but lots of moving parts and could die if in storage for a decade.
SSD & SDcard: both start losing charge if not powered after ~5 years.
Tape (LTO) trouble with gen9, issues with drive-tape backwards compatibility, rather expensive.
Blu-ray: archival grade Panasonic is great but impossible to buy in Europe. M-disc is expensive. I have doubts of drive availability in the future.
Cloud: not for archiving; imagine trouble paying the rent because a transtacion fails leading to destroy your archives.
Any other options I'm unaware of?
I worked in the TV industry a few years ago, and LTOs were (and still is) the only viable archiving technology for heavy 1080p (or 4K, now) videos.