I really hardly manage to feel inspired, and "vibed" by one piece movies, probably due to their duration - which is very low in order to settle a real background, since it's the main feature of one piece tbqh - and the fact that we know the pattern very well, moreso than in the manga itself.
But i would say it's a tie somehow probably between Z and the Shiki's one.
And if we only talk about the scenario, then probably the film with the flower dude, that was also the darkest one piece's film, which is what lacks in OP universe imo - less and less let's hope since we are reaching the EOS.