I spent extensive time evaluating this problem, and tried a whole bunch of different things:
Nextcloud, Resilio, iCloud, etc etc etc.
Honestly? Just using Google Photos is probably the best bet for most folks, whether you’re on iOS or something else. I personally picked OneDrive for my use case since it is both more performant for large data sync and 6 TB + Office 365 for a family plan beat out the alternatives on pricing.
Eh... I'd definitely do a Google Takeout to verify everything's OK before you delete your originals.
You may think the downsampled image is sufficient for lossy backups, but older images stored in "high quality" in my personal GP library were almost wholly stripped of metadata, including when the photo was taken.
(Many of my users have suffered from this as well, which is why I built tag value inference into PhotoStructure to try to help spackle over these metadata holes).
That’s good advice for those that care, and I should have mentioned it, especially for HN crowd. I definitely noticed this problem when I did Google Takeout on my photos dating back to the Picasa days.
I still think that for most people (and on HN, where we care more about fighting data entropy, there might be significantly lower overlap with the majority), Google Photos is the best option.
Nextcloud, Resilio, iCloud, etc etc etc.
Honestly? Just using Google Photos is probably the best bet for most folks, whether you’re on iOS or something else. I personally picked OneDrive for my use case since it is both more performant for large data sync and 6 TB + Office 365 for a family plan beat out the alternatives on pricing.