would be awesome if you’re able to integrate maestro support. It’s very common in the Netherlands, Belgium, Germany, Austria (and more?) and many banks give them out by default. Meastro is often supported together with mastercard (as it’s from the same company) at shops over here so it wouldn’t be a big loss to just carry your card around instead of the maestro card.
A big plus would be a dual sheme card (maestro and mastercard) as some older / smaller shops still just support maestro.
Fidor (a german “fintech” who is good in loosing customer and they even tried to sold their bank for 1€…) offers such a card for example called Fidor Smart Card where you get one card which supports maestro & mastercard together.