I found firefox send as a quick fix for a unique file sharing option.
the file is offline after 24 hours or a number of customizable downloads, whichever comes first. so that corrects the sharing with the client I hope.
I think using the plans of the editing software you use can be helpful. Lightroom's Creative Cloud provides 1TB of visible space on all devices. what is the maximum that I have ever come across and the editing is also a simplified experience.
otherwise, Apple Time Machine backs up the content, but since I'm not a user, I do not know about sharing and accessibility from multiple devices.
A fairly radical idea uses GitHub but these will only be free public repositories. the payment is there to make private records but the good point of unlimited space is still there.
I hope it helps.