Well, I can confirm that the first beta of macOS 12.0 seems to run without any quirks on my iMac Mac (Retina 5K, 27", Mid-2015), model identifier iMac15,1. WiFi works, Bluetooth works, accellerated graphics work (AMD Radeon R9 M290), sound works……
I don’t get why Apple wants to ditch my iMac in first place. ?
I mean, come on…… just because it’s not LATE 2015 but Mid-2015! ?
It has 5K! It has AMD-graphics! It has a damn 3 TB Fusion Drive. Really, Apple!
And just using that nightly build of OpenCore-Patcher seems to be enough to prove macOS 12 to run just like Big Sur.
Now, that is a bit of a let down. I hope this state (of working just fine with OpenCore-Patcher’s EFI-bootloader) will persist all the way through the release of macOS 12 Monterey.