HI Rik!

Thank you for the feedback! Mollie is not slated to be made compatible until 3.0, and even then may be shortly after the 3.0 launch. But don't worry, we have a plan for this, including making sure that 2.x forms continue to work (with Mollie) in 3.0.

You can read more about this in detail here: https://givewp.com/documentation/resources/donation-form-builder-common-questions/#add-on-feature-support