Right. RPO is Double Option (give/keep) off of zone blocking with an unblocked read guy in which all of that action sets up a pass. Watch out for receivers who aren't blocking or who release from a block too early.
I feel that, in the NFL, it's give/pass most of the time. Guys like Lamar Jackson or Kyler Murray might keep more often than other QBs running that play, but it's probably not a good idea to keep more than a few times each game.
Scouting will tell the D from which formations and personnel they can expect RPO and what to do when they see it.
Of the three possibilities, which has the greatest chance of a big play? Probably pass. That would mean the double option look prioritizes pass D with the goal of preventing big runs.
I agree with Butler, play your D and do your job. Plenty of video study and a good scout team O will eliminate the fear factor and make RPO just another play to be expected and for which there is a plan to defend it.