I have never felt comfortable with having my phone pictures in the cloud and preferring only Dropbox(supporting Linux properly), since Google retired picasa and Apple only really worth while if you ONLY use apple products despite what fanboys might say, I decided to avoid vendor lock-in. I have exchanged my iMac and MacBook with Lenovo Yoga 2 Pro(Qubes 3.2) and a Purism Librem 13v2(Qubes 4.0).
I want my data to be @home, without being accessible from the internet. No unnecessary risks of breaches, if avoidable and no access from a giant attack vector(The whole internet if it is in the public cloud). Private cloud it is. And NextCloud seems to be best of breed.
Bought a CubieTruck and enjoyed the easy install of NextCloud, easy updating automatically, easy setting up the iPhone part, etc.)
Not a usual guide, but a simple heartfelt recommend from here. Try it out. You won’t regret it.