Have you triedYou can add refind to its own partition and add the appropriate core services folder and get refind showing in the system preferences prefpane. In theory that should tell refind to boot by default after OC. I had started down that path with my 3,1 but simply hadn’t the time to finish. I think the “connectdrivers” thing was killing me. As I could chainload sometimes I just didn’t realize why The behavior changed.
the install for refind calls this “ownhfs” but it does also work with apfs formatted drives. I didnt use the refind installer I simply manually placed the files in the right path and they showed up in the prefpane boot selector automatically.
GitHub - abdyfranco/next-loader: Next Generation EFI-Based Boot Manager designed for Intel Mac.
Next Generation EFI-Based Boot Manager designed for Intel Mac. - abdyfranco/next-loader
github.com