With the Sources API, every customer had a default_source, but when using SetupIntent (in order to be compliant with the PSD2/SCA directive), there doesn't seem to be any direct equivalent.
So my question is, how this can be properly represented API-side (without using metadata)?
The payment_methods listing seems to have a property called preferred for the card (which seems to be what I am looking for), but so far I have not found out, how to get/set this property.