Having a hard time installing Win10 on a 15,1 iMac running Sonoma 14.5 with OpenCore 1.5

This 15,1 iMac is running Sonoma 14.5 on a 2TB SSD on Drive 1, and this computer has the small Nvme on Drive 0 which has High Sierra. The computer boots automatically into Sonoma. I do not use the Nvme for nothing.

I get this error on drive 1 when on Windows10 shows all the hard drives before installing. The error I get "We couldn't create a new partition or locate and existing"

Is it because I'm using Drive-1 instead Drive 0?

I have tried Mr Macintosh videos 1 and 2 on YouTube installing windows 10, and they do not work-Which would seam easy to use BootCamp.

I tried going the Rufus way-Which involves formatting the USB in NTFS on a windows machine. I get the same error-"We couldn't create a new partition or locate and existing"

I tried another approach where I boot off the USB flash drive, and I go in and modify the Registry to bypass "TPMCheck", "RAMCheck", and "SecureBootCheck"

Any tips or suggestions? I want to stay in the open-core blanket to avoid the risk of "Bricking the iMac"

I have successfully installed Win10 on two mac's of 8,1 MacBookPro 13" and a 12,1 iMac 27"

Thanks