Need help with an iMac 8,1

I've been trying to use opencore to install big sur on my iMac 8,1 for a while now. It has no os on it all all, completely blank but working drive. However every time I boot opencore (followed the instructions on the website from another Mac to make the install usb made sure it was set to iMac 8,1 and installed the patch to the usb and select efi boot when I turn on the 8,1) it will start to boot Then hang for a minute or two and it will show the prohibed simbol with the apple support link with garbled text all over the screen. I've tried 3 different usb drives and and Ventura instead of big sur. Any suggestions?

submitted by /u/ADumbasswithAPC
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