Issues with installing OpenCore Legacy on an iMac 2012

Hi,

Can anyone advise on how to resolve the issue with installing macOS Sonoma on my iMac? I have a 27" iMac Late 2012 with an Intel Core i7. I can't install OpenCore Legacy Patcher on it. I've already tried different versions of macOS and different versions of OpenCore Legacy Patcher, but nothing works. Initially, the installation goes smoothly for about 30 minutes; the iMac restarts several times, but at the final stage, after another restart, the progress bar stops moving, and the process freezes. Nothing happens, no matter how long I wait. I can only turn off the iMac with the power button, and after turning it on again, the process freezes immediately. I had the same issue before with my 2012 MacBook. I can use this same USB drive without issues on another iMac, but I can't get the new macOS to install on this one. Can anyone suggest what might be the problem?