Yes, I know that issue. My approach probably isn't the most sophisticated one, but rather pragmatic:
I periodically upload photos and movies taken with my mobile to a cloud service. This ensures safety and availability as they offer triple safety.

When it comes to large, high resolution photo files (Raw or TIFF) format as well as to HD or 4K video files, I also use external drives that I occasionally mirror. I also keep one copy in an external deposit box.

I also try to clean my database as often as possible, i.e. delete images of the same series, event, etc. that do not belong to the top 10 or 20%. I also cut and edit movies, keep (and save) the final result and delete the uncut raw material. This helps me keep my data load manageable.

Please let us know the result of your research ;-)