That's what they're doing, generating a key using post-quantum crypto and using it as the PSK - from TFA: "The tool establishes a symmetric key and provides it

That's what they're doing, generating a key using post-quantum crypto and using it as the PSK - from TFA: "The tool establishes a symmetric key and provides it to WireGuard. Since it supplies WireGuard with key through the PSK feature using Rosenpass+WireGuard is cryptographically no less secure than using WireGuard on its own ("hybrid security"). Rosenpass refreshes the symmetric key every two minutes."