It seems that the options for backup are:

1. Use takeout to get a single backup.

That's it.

There is no way I can tell to get incremental backups. It seems that there used to be[0][1], but some permissions changes on Google's side made them impossible.

Is there really no way to do this?

What alternatives are worth considering for a cloud based photo tool, that actually allows you to backup?

[0] https://rclone.org/googlephotos/#limitations

[1] https://github.com/gilesknap/gphotos-sync