I thought he did a great job playing the murder victim in Tropic Thunder before he even made it big, I think he can find plenty of similar work if he's willing to keep his ego in check...
If according to that prophecy that is the only condition to becoming the Messiah, sure, he'd be the Messiah to the religion that follows that specific prophecy.
The fact that the prophecy has been invented as tool made to manipulate people does not make it not true. Paul is using psyops, and is also the messiah. Accept the duality.
You know, I love that despite Bladerunner 2049 flopping, Denis decided to make the dreams of his nerdy teenage self come true and take on the monumental taks of adapting Dune, and basically all of Hollywood's rising stars were like "fuck yeah let me get in on that".
In hindsight I have no idea how it happened, but I'm glad it did.