I have already explained my issues with the whole Carrot traitor theory before so I'm not going to go through that again, imo the traitor is one of the Nine Red Scabbards and the one I'm leaning towards is Kanjuro.
I find it very strange how Kanjuro is the only scabbard other than Denjiro(who we still don't know where he is) that got the least focus, Kanjuro was the second one introduced after Kin'emon and before Raizo yet characters like Raizo, Ashura Doji, and even Kawamatsu have all so far gotten more focus than Kanjuro. Kanjuro was only focused a little bit here and there but not that much and I find that a bit strange, this makes me think that Oda has something big planned for Kanjuro's character.
Other than the minks the only other characters that knew about Raizo being at Zou was Kin'emon, Kanjuro, and Momo, the minks knew where Raizo was located at Zou so if one of them was the traitor they would have secretly told Jack were Raizo was. Jack only knew that Raizo was at Zou but didn't know his location at Zou, someone must have informed Jack that Raizo was Zou but since this person wasn't at Zou they didn't know where Raizo was located and again the only other characters that knew Raizo was at Zou but didn't know where he was located at Zou was Kin'emon, Kanjuro, and Momo.
We can obviously rule out Momo and we've seen plenty from Kin'emon's character to rule him out so that only leaves Kanjuro, also I find it weird how Hawkins and Drake knew to check the bath house were Nami, Robin, and Shinobu were. The only other characters that knew that those three were going to the bath house were Brook and Kanjuro, obviously it's not Brook so that only leaves Kanjuro being the one that told the Beasts Pirates and Orochi's forces about the bath house.
Also back during the Dressrosa arc, Doffy somehow knew about Momo and him being alive so how did he find out about that? I'm guessing that when Kanjuro got captured at Dressrosa he found out about Doffy's alliance with Kaido, and then told him some information with one of those information probably being about Momo. This whole traitor reveal has to be someone that would really surprise Kin'emon and the others and it has to be someone that they least expect, and what better way to really surprise them is if one of the scabbards specifically Kanjuro ends up being revealed as the traitor.
Lastly I wanted to point out this fun little fact I learned, in real life there was the whole Shimabara Rebellion and one of the rebels was a man named Yamada Emosaku. However Emosaku was secretly an informant for the Tokugawa shogunate, and he ended up betraying his fellow rebels and on top of that he was also a painter.