Your roller brake is likely out of adjustment or has the wrong ratio cable pull or some similar issue. If it needed service, they have a tendency to be instantaneously grabby & stop the wheel cold. That's not to say it can't be worn out. Just unlikely. Fortunately they are cheap and a lifetime supply of the grease is cheaper.
Adding rim brakes turns the wheel into a wear item. Ultimately wheels are the more expensive repair. Having said that: If the fork crown is heavy gauge material & you can drill a hole...Why not? You'd need to make sure that your prospective calipers will A) Have enough reach to get to the rim & B) Have enough clearance to reach around your tire.
Part of what makes a Dutch bike a Dutch bike is it's utilitarian, low maintenance, weather-proof design. Rim brakes are a departure from that ethos.
Last edited by base2; 01-21-24 at 12:28 AM.