Questions about Sapphire GearBox

That should not be a problem. However, I recommend an AMD GPU because as far as I know they have better drivers for Linux.

It is possible, but the procedure is long and it is not 100% guaranteed, (risk of errors). It is more a question of compatibility between the graphics card and the computer than the case according to my research. "What is the best eGPU for Boot Camp is a question we have seen a lot. The answer is a sad joke that long-time Mac users understand all too well; get AMD graphics cards for macOS and Nvidia graphics cards for Windows. An AMD eGPU to control everything in both operating systems is possible, but you will have to work for it. If you decide to go with the green team, stop reading further and hot plug the eGPU into your Mac. More than likely this will work without too many problems. For the red team, get ready to go on an adventure called error 12. We have learned that the version of Windows 10 can make a huge difference. Currently, the recommended version is Windows 10 1903 OS Build 18362.295. This is for AMD Radeon cards with native macOS eGPU support and can run in Boot Camp." Otherwise Apple's support offers this: https://support.apple.com/fr-ch/HT208544

So the eGPU does need additional power. The eGPU housing has one USB-C/Thunderbolt 3 connection, two USB-A connections and one Ethernet connection. The video connections that you can see in the product image are from the graphics card used and this is NOT included. The included Thunderbolt 3 cable is approx. 30cm long.

I think so, the Zenbook Duo has a Thunderbolt 3 or Thunderbolt 4 port, right?

Yes, that fits. GPU support: GPU Type: Single/double slot, full length, PCI-Express x16 graphics cards. Max. GPU dimensions: 266 mm (L) x 125 mm (H) Max. GPU power consumption: 300 Watts