Double check the numbers (I checked these maybe a year and a half ago?) but for 4 bays/drives or less, just get a Synology. Amazing price to performance ratio and synology make a good OS
If you want more than four drives? Do you “love linux”? If so, go with a Truenas or a Ceph build. Do you want it to “just work”? Unraid.
So based on your use case and comments: Just get them a synology. Then either use the Synology Drive Client software, set it up as a smb share/network drive and have them manually copy files in, or go semi-crazy and run Nextcloud.
That said: if the focus is on photos and videos, you may just want to look into google drive or one of the other user oriented cloud services. Fairly inexpensive and, unless you are filming a lot of Those Kind of Movies, the loss of privacy knowing that your birthday pictures will probably be used for an internal training set are offset by having firm backups and one less thing to worry about in an emergency.