Why is the asymmetry a show-stopper for you? It would seem like having lots of E-cores would be advantageous for compiling, and still having some P-cores means you don't lose performance when linking.

Because Windows has a pants on head design choice where processes that aren’t the active window get shunted onto the e cores regardless of whether they are doing lots of work or not. I halfway suspect that this is intended as a market segmentation trick by MS