[dmix]

I've been using Syncthing for years: https://syncthing.net/

It's entirely P2P, so no 3rd party hosting of your files, no trusting someone's crypto/update schemes, or having to set up your own servers (although you still can easily add it to a VPS if you want offsite). There's also a nice mobile app:

https://play.google.com/store/apps/details?id=com.nutomic.sy...

You can also securely share directories with another person who uses Syncthing, I've found autosync directories are easier than using something like Airdrop for sharing photos with family.