Infiltration and working for Sword will, I think, be the safest option. Basically just what he said to Smoker. Needed some sort of independance to try and take on certain tasks, taking down Blackbeard being the one he’s opted for. Plus some increasing disillusioned feelings about the Marines.
Most interesting? Genuinely thinks Blackbeard can change the world for the better. A Kuzan at genuine rock bottom after his defeat and in despair over the state of the world buying into Blackbeard’s plan to tear it all down would be a interesting place to take the character. Doesn’t really fit with him warning Akainu about Doffy, though, so very unlikelu.