Direct injection coking has long been a thing of the past for smarter car companies. All they had to do was use port injection to clean the runners and valves and it becomes a non issue. Alfa does it, Toyota does it, Subaru does it. Those are the only companies I have worked for that I know for a fact that do it. I have cleaned up a Mazda Miata engine where coking was causing misfires and it fixed it so maybe they have fixed the issue too. I know the Germans can’t figure it out for some reason and are creating some super pcv as an over complicated fix. Wow that became a rant. Sorry.