Ah, ok, the replacement board is working well enough to generate errors then, which means it wasn't DOA, just FOA (a less commonplace technical term). Is this the replacement Prime Z490-A (though I'd guess you'll be waiting longer for that) or just another one to use in the meantime?
It's probably best to wait for a replacement of the original board in any case. For a little inspiration, my upgrade to Monterey (using OC 0.7.4) on the same board went smoothly. There's a general issue regarding the current lack of Bluetooth support (which I don't use anyway) but everything else seems fine using my OC 0.7.4 EFI folder from Big Sur installation. There. Inspired?