its not. Katakuri was near invincible with it. Wano Luffy's CoO should be on a similar level.
for apoo, you most likely cannot dodge his attacks. His attacks are transmitted through music itself. Unless you are kizaru, you most likely cannot dodge sound waves. As long as you are in his range, you will be hit. This is the same reason why Apoo was able to land a slash on Zoro, who has pretty decent CoO.
If apoo was able to land several hits on Luffy, and luffy is a known user of advanced CoO, maybe the question isn't "is FS overated" but rather "how hax is apoo's ability?"
Also, it seems as if luffy actually was able to use FS to predict Apoo's attack. Zoro said that Apoo was about to use another attack and Luffy stated he already knew. The issue wasn't that he couldn't predict, its that he couldn't dodge.