Please read the original and the third post, this remote networking technology has existed for a few years now and it is free for personal use and it is called Tailscale. The post link below shows Tailscale in action in a mobile app, but it works as well or better with any desktop (Linux, macOS, Windows).
The WDC MCH development team could make this easier by supporting Tailscale natively as a Debian client but the mesh VPN network functionality already works right now with a Tailscale subnet router. Many Synology and other NAS already support Tailscale.
Copying entire folder remotely from Android phone to My Cloud Home private space (Public space and two way copying and sync also possible) with Tailscale and third party Android file manager, without the use of My Cloud Home mobile app. Tailscale supports Linux, macOS, Windows, iOS and Android.
