Hello James Poole1,
Thanks for reaching out to Microsoft Community. I understand how important this set-up for you.
But apparently, the only way to automatically connect to the accessories and peripherals connected to the Dock is by connecting the Surface Connect cable on the dock to your Surface device. That means, yes, in order for Surface device to integrate with the Dock is via the Surface Connect cable.
I hope this clarifies your concern.
Let us know if you got the help you needed by clicking Yes orNo.
Kind regards,
StevenK