Hum,
let me answer per points:<p>0. I may empathize BUT if you value data on them... Well you ask something like how I can have my wife drunk and my barrel full (ancient Italian proverb). Sometimes you can "optimize" your storage for instance lowering a bit quality of images that you may do not need at super-high resolution, stripping metatada, change formats, ... Depending on the case you may save big size of storage.<p>1. Why not having a more flexible backup then? RClone is a nice tool if you need to use someone else computer and you may use various vendors, also rsync+something you can mount as a local filesystem may also enlarge market offers list...<p>2. No proprietary tool can be consider trustworthy, no service will take care of your stuff better then yourself...<p>To answer more directly: I do not feel the need of buy someone else resources for storage, however consider a thing: local backups may not be super reliable, may be stolen, lost etc. however if you properly store and use these kind of event are not much more likely to happen than a "disaster in the cloud" especially from cheap services that in turn themselves re-sell someone else resources. IOW my own personal suggestion is assembly/buy a decent PC, with enough PCIe ports to support many sata port, fill it with reasonably big plate disks at the best price/Gb ratio you are able to find, install a GNU/Linux distro you prefer or pay someone to do so for you, I suggest using NixOS because being declarative if something goes wrong recovery will be quicker. Create a proper raid structure and use that as a personal cloud.<p>File transfer from various device may vary depending on the source device, from Syncthing to rsync+webdav you may have many options. It's automation again highly depend on "sources"...<p>To serve your content GNU MediaGoblin may be interesting, simply locally mount your server storage via nfs and use any local tool you want may also be an option.