If you want to run monterey then remove your 1060 and use the iGPU to install Catalina first. That way you can map all your USB ports and make sure they work. See the guide by UtterDisbelief for how to do that.
After that, you can make your Monterey USB installer, hopefully with OpenCore and have your 6600 installed. A clean install would be best as you are probably using Clover bootloader right now.
I don't see any guides here but there is one older one on Github that might be helpful to a degree.
Gigabyte Z270X-UG "Hackintosh". Contribute to icedterminal/ga-z270x-ug development by creating an account on GitHub.
github.com