Ask HN: How do you back up your large-storage phones?

Nowadays everybody in my family uses 256GB-storage phones, because we hate to run out of space when taking photos or videos. I'm currently doing the manual USB sync of the phones every couple of months, moving data to a NAS. That in itself is painful, it takes hours for the phones to even go through the hundreds of gigs of data over USB. An incremental backup would be far nicer!

But between the backups we have no data backups except using the low-quality free storage provided by Google Photos (yes, even on the iPhones).

I'm afraid of losing the data between the backups if the phones get lost/stop working/etc. What online/sync solutions do you use to incrementally backup your large-storage devices?