Jens Banks are not all connected to the same systems. See: https://www.betaalvereniging.nl/betalingsverkeer/instant-payments/deelnemende-banken-instant-payments/ Some banks also have differing levels of support depending on the payment processor. For example ING sends instant payments outgoing through equensWorldline, but they do not send outgoing instant transfers through TIPS, even though they're connected to it.
As bunq has more of an European focus, they are connected to both EBA Clearing (RT1) and TIPS and fully support both of them for incoming and outgoing instant payments. But they're not connected to equensWorldline, as that is just a domestic Dutch system. As soon as the other Dutch banks start to fully support TIPS, then this won't be an issue anymore. In the meantime, I can only recommend using bunq payment requests.
