Have done this route Nancy tines, as it’s cheaper and easier than going down to London.
Fly over from Birmingham the night before (cheaper than booking a through ticket)
Stay overnight in the Premier Inn a 2 Euro return bus.
At Dublin it’s easy to get to the checking desks and the big benefit is you go through US boarder and Customs at the airport, so you arrive into Orlando as a local flight, go to tge carrousel, pick up your bags and off you go.