If Apple is compelled to allow users to run unsigned binaries (like Android) - would that allow for JIT emulators to run or is there something fundamentally blocking the execution of JIT code in iOS that prevents this?
iOS itself almost certainly also blocks usages of that API as well, unless the binary is signed with the correct entitlements.
But if Apple was forced to allow any binary to execute, and utilise any entitlement/API, then yeah there’s nothing stopping a JIT emulator running on iOS. But I think it’s very unlikely the EU would go that far, I don’t think such actions are needed for the EU to achieve their aims (liberalisation of app economy and markets).
It's just that apple block any submissions using that API from the app store.