What about Aoba stating that Kisame was relative to Itachi, who repeatedly fodderized Orochimaru?
This is an extremely charitable interpretation of their overall portrayal.
1. Aoba never said they were on the exact same level in PL bro, he said after witnessing Kisame kill himself to protect his secrets, that he was fit to be partners with Itachi. Not some amazing feat of power, let's not get to Zboy tier leaching here lmfao.
2.It doesn't change what we already know, the strongest Akatsuki members are not partnered with eachother. Pain is partnered with Konan, Obito is partnered with Deidara(who isn't weak, but he's supposed to be weaker then Sasori, matchups aside), Kakazu is partnered with Hidan.
3. Itachi isn't ever shown really being super impressed by Kisame's power, what we actually see is both of them respecting eachother as teammate killers, the real reason they're partners.
4. Even if Aoba genuinely believed Kisame is relative to Itachi, it would just mean he has bad intel and doesn't know how strong Itachi is beyond what he showed against Kakashi, which is barely even MS, certainly not the likes of Susano, Shisui's eye, Izanami or the totsuka blade and yata mirror.
5. Kisame is Obito's underling, Obito believed Itachi could have killed him
who repeatedly fodderized Orochimaru?
Nah, with his hydra form had Regen, and he wasn't worried about Susano attacks until Itachi was able to seal him with the Totsuka blade. Same with the first fight, he lost a hand, but he can regen, and ultimately got away.