After the new macOS boots, run OCLP again and click “Post-Install Root Patch.” This is the actual “jailbreak” moment—it rewrites system kernel extensions to make your Wi-Fi and graphics work.
from the official GitHub repository (Dortania). jailbreak macbook pro 2012
Run the app, click “Build OpenCore,” then “Install OpenCore to USB drive.” After the new macOS boots, run OCLP again