These regulations were the reason that American Express pulled out of various European markets (but not all) as it became less/not profitable for them to issue their cards in those markets.
Co-branded Amex cards essentially became considered no different than 4-party cards and stopped being exempted from the cap interchange in 2018. Nothing changed for Amex proper. How would you even define interchange when it's indistinguishable from the scheme fee?
There's a reason every European PSP charges 2-4x higher fees with Amex cards.
