You have to disable CSM in order to boot into Hack. If you want to back into Windows, just change the CSM back to enable.
I'm not sure I understand what your issue is...have you transferred the EFI partition (with the OC configuration) to the macOS boot drive (which makes it so you don't need the USB drive in to boot to OC and then macOS)? My Crosshair VII doesn't have the issue your describing and I've never seen anyone with a Crosshair VIII mention it either. I have CSM disabled and have no problems jumping between Windows 10 and macOS Catalina, either using OpenCore or using the BIOS's boot picker (spamming F8 on boot or just switching the default boot device in the BIOS), regardless of which NVME slot my macOS ssd is in.
I'd suggest you jump over to the AMD OSX Discord for AMD Hackintosh support (and also never follow youtube videos for hackintosh help; they're almost always out of date and won't help you when issues come up in the future)
Yes, i have transferred the EFi partition on the macos drive but if i remove the pendrive my computer boot only in windows! Is like don't want boot from MacOs drive.