Samsung is sitting at 28% of the Western European market share with their Android phones. Should we be worried about anti competitive behavior there as well ?

Because companies compete globally, not just locally?

Apple isn't building features to compete with Samsung only in the US. It's a global dynamic. Local competition is restricted to tiny subsets of features.

And it's only 57-42 for Apple in the US anyways. If it were 90-10 then sure. But 57-42 is what you get with strong competition. Having a majority doesn't mean there's a lack of competition. It just means one company is currently ahead, as one of them usually will be when there are two main players.