For your first question, my guess would be its the largest fish. Proton probably has some users that harbor useful information but think about apples market dominace. It’s massive. And as far as I know, proton doesn’t have a business presence directly under UK jurisdiction; Apple has an enormous presence and billions in previous investments for employees and infrastructure there. Making it much easier to enforce those laws on them.

In other words, it’s like living in the country versus living in another country. My home country will have a much easier time forcing laws on me than a country I’m not even living in.

I’m unable to answer your second question though. I don’t know enough about legality.