(FOR MAC)
In case this helps anyone in the future with a similar problem…on UE5.3 I am working on a Silicon Mac and trying to also do an Intel compatible package…once you load up the UE app using Rosetta, when you go to cook content you get the same message. It turns out selecting “universal” packaging settings under mac won’t function correctly. You need to actively switch the architecture for all four drop down menus from “universal” to “Intel” within project settings. Once I did this, the cooking happened as intended.