Safely remove macos

Hello guys. I currently dual boot macOS and windows on same drive and now I want to just get rid of macOS. It is very slow and lags as hell. It’s a very weird problem. When I boot into my hackintosh it’s performs fine. But when I connect to the internet after a few seconds everything starts to lag and it performs like a potatoe until they’re is no activity and then laptop goes to sleep. When it’s awaken then it perform fine. I don’t even know what causes this issue nor do I want to fix it because I just want to use windows. And yes I have igpu acceleration . So now my question is how do I remove macOS and open core without touching windows. And how do I deal with efi of windows..currently open core is the boot loader for both operating system. I want to remove everything except windows so how can I do it. Any help will be appreciated.