Google Drive was the integrating factor till July this year. It was possible to sync photos with Drive. Drive also works with ios.
Now that it is discontinued, there is no automatic way to upload but from Photos settings you enable sync to drive (tap on the cloud icon) or using the share option upload to third party cloud/messaging/mail options.
I actually solved the problem, in Samsung device or take any android there is a feature called storage booster which automatically deletes unnecessary data as multiple same photo form device so you have to turn it off to keep your photos in your destined folder
just go to settings>device care/maintenance > storage > storage booster > auto delete unnecessary ...