Hi 👋 Johannes-Teal-Dragon
Are you talking about ING Netherlands or Belgium? Both are not connected to the same system as bunq . In addition, I don't understand why you should incur additional costs. A regular SEPA transfer is in any case via bunq free, and will in no way be 'more expensive' than a SEPA Instant Payment, if that costs extra.
This topic is also specifically about Instant Payments between bunq and Argenta Belgium.