Hi C-pher,
What you are referring to is an accessory that has not been sold since nor works with any product beyond Surface Pro 6. All newer models come with a USB-C port already.
The solution for your use case is to get a USB-C Hub or Dock to extend the number of ports available to you. Here are some options for you, you can select the best that works for you and your travel needs.
- Accessories Designed for Surface (microsoft.com)
- Buy Microsoft Surface Dock 2 – Microsoft Surface
- Buy Surface Thunderbolt™ 4 Dock (Ports, Compatibility, Price) - Microsoft Store
The Dock 2 may be a good option to think about as you could then no longer need to carry around a separate 200w power supply as the Dock 2 provides the same wattage and Dock 2 uses the Surface Connect port so you are not using up a USB-C port on the device to connect it with.
If you want to keep your 200w power supply and minimize what you need to pack around, then I would look at the smaller form factor Designed for Surface USB-C hubs that have pass through charging.
Hope this helps,
Greg