From the release note above, I guess FEX would have been the "Rosetta 2" for Asahi but seems to be also out of the question ATM so you are right no Proton indeed for the time being. I didn't know Proton was WINE-IS-NOT-an-EMULATOR based thanks for info :)
>There is a category of software that will likely never support 16K page sizes: certain emulators and compatibility layers, including FEX.
Well, too bad...