Easiest way to handle GPU switch? (Nvidia to iGPU) (Since we can't have nice things)

Hey.

I was thinking about getting some HDMI splitter (2 inputs to 1 output), so i could use nvidia on windows and iGPU on Hackintosh. Is this easiest way to handle situation till drivers will be ready? (so, never) Or does You guys handle it somehow different? Is this even possible to be set up only once? Or i need to block my iGPU in bios every time i use windows and block nvidia when using Mojave? Do you guys know any splitter capable of auto switching source?