Hello M-J_J_B,
Welcome to Microsoft Community.
In fact, since the launch of the Surface Pro series, the size of the Surface Connect port has never changed, and in the past generations of Surface Pro devices, the port has always appeared on the right side of every Surface Pro device.
Special devices connected to this port are generally:
The power requirements of different models of equipment are different, so the power of the power adapter used will also be different, so the supported charging data is in the first link above.
But if the problem involves other parameters, such as data transfer speed, video resolution and refresh rate, Ethernet speed, etc., then this is actually determined by the Surface Dock or Surface Dock 2, because the Surface is only connected to a dedicated docking station. To transfer data, connect to external displays, and use Ethernet, all of which are in the second link.
As a supplement, here are the external display resolutions and refresh rates supported by different Surface devices:
Supported external display resolution and refresh rates for Surface - Microsoft Support
As for "Thunderbolt compatibility," I probably don't understand what you're asking, because the Connect port itself is not directly connected to the Thunderbolt port, so the compatibility should be related to the Surface Dock port. Unfortunately, neither Surface Dock nor Surface Dock 2 support the Thunder protocol.
Surface Dock 2 overview - Surface | Microsoft Learn
The current dock that supports the Thunderbolt protocol is the Surface Thunderbolt™ 4 dock, but it is connected via USB-C instead of the Connect port.
Some models of Surface Pro series devices come with USB-C ports that support the Thunder 4 protocol, such as Surface Pro 11.
So in fact, I may not be able to give a clear answer to your question. Future Surface Pro devices may still have Connect ports, unless the designer team has a new inspiration in the future. As for Thunderbolt 5, I suspect this feature may gradually be prioritized in the USB-C ports of some Surface series devices.
Are there any questions? I will answer everything I know.
Best Regards,
Mitchell | Microsoft Community Support Specialist