How to determine if my app's credit card has been added to apply pay of my device

Im trying to implement add to Apple Pay feature in my app. I have an issuer bank's credit card as an existing feature.

Now question is, say its added successfully already, I relaunch my app, how to tell if already added to Apple Pay?

I have made some reads, and asked AIs, but I can't seem to get a clear answer.

1. Passkit's primaryAccountIdentifier - if use this, how will our backend store this? I mean, I don't think its ideal approach for mobile app to be responsible for calling backend api.
2. deviceAccountNumberSuffix - what if my app have other cards that can be added to Apple Pay and has same suffix. Then seems broken flow.