For anyone reading this 2023 - I just tried this and it works without any need for special drivers. This is what I did:
1. Buy 1 x m.2 NVME drive and 1 x 2.5" SSD drive. You don't need to buy anything particularly quick, a standard NVME drive works perfect, BUT you MUST have both NVME + 2.5", you can't use just one of them. And advice - Use two of different sizes, that will remove some confusion when you install the OS.
2. Disassemble the unit. You don't need to be computer mechanic to do it, just methodic and careful. You need TORX 8 + 9.
3. Download and make a Windows 10 USB.
4. Install on DRIVE 1 for m.2 drive (NVME).
5. Follow instructions on screen
6. Download the Surface Studio Drivers pack and add the missing drivers.
This device has reached the End of Servicing. The following packages are no longer being updated with latest drivers and firmware.
www.microsoft.com
END RESULT:
My unit was overheating and CPU throttling to the max! Now, works like a dream!
Advice: While you are doing it, make sure to vacuum both fans, and remove all dust you see. Doesn't hurt to REPASTE the CPU and GPU while you are at it, mine was very dry to say the least.
Take your time, don't rush it! A cable broken might give you a lot of headache! Make sure you use the same screw for each position. Mark your work and label it sequentially.
Good luck!