> There is no simple path.

As with most broad societal things, I don't think anyone thinks so either.

There is for sure a "simplest way" of doing it though, question is what that is.

> Even the places that have successfully legislated this are struggling with enforcement - EU is dealing with extreme and prolonged compliance issues three years into enactment

Huh? The EU does not mandate countries to implement laws around "OS must allow the installation of an alternative OS from any third party", I'd be very aware of such a law if it existed I feel like. Are you talking about some future regulation they're discussing or something?