The EU only capped interchange fees, which is the amount that goes to the bank that issued the card. It did not cap the fees that go the your PSP. Which makes sense, since you can pick the PSP you do business with, but you can't pick the bank that issues your customers' cards.

(And I don't think it applies to US merchants like you anyways)

https://ec.europa.eu/commission/presscorner/detail/en/ip_15_...