I am Italian, I bought in Italt through an Italian gray market distributor and it is all right. I have switched language, I have already update the camera firmware and all work well so far.
Were you able to register the camera with Canon Professional Services? Have you tried that? I am in the UK, and the only R5s that are available are from grey market sellers. Some have great reputations and offer long warranties, but I'm worried about being able to register the camera properly.