Hello, kulderas.
Welcome to Microsoft Community!
The first thing we can say for sure: Surface Laptop Studio does support USB4 and Thunderbolt 4, as you can see in the link below:
Surface Laptop Studio features - Microsoft Support
Meanwhile, I noticed that you have already tried many steps such as updating the drivers and system, forcing a reboot of the device, replacing the cables, and so on.
I believe you have already obtained the driver and firmware installer for Surface Laptop Studio from the link below:
Download Surface Laptop Studio Drivers and Firmware from Official Microsoft Download Center
If the problem stems from the system or drivers, we can usually solve the problem by installing drivers and getting Windows updates.
But now that the problem persists, we need to further consider hardware or connectivity issues.
For cable accessories for Surface devices, allow me to provide you with the following link:
Accessories Designed for Surface (microsoft.com)
Here are the official cables from Microsoft for Surface devices, using these cables will minimize hardware compatibility issues.
Additionally, I think at this point we need to perform a hardware check on the Surface Laptop Studio's ports. I recommend that you send your device to the Surface support team for a hardware service.
I can direct you to Surface Live support, who can help you create a service order:
- Use your personal Microsoft account (not your organization account) to access the following links:
- Type Surface, press Enter, and click "Contact Support" at the bottom:
- Select Technical Support and select the device model you are currently using in Produce family, then click Confirm:
- You will see contact options for Chat support and Phone support, please contact them during business hours:
I wish you all the best.
Best Regards.
Leo.L - Microsoft Community Support Specialist