nothing that indicates he can tame an admiral.
BB always hides his power. Thats what he did for years in WB crew.
Nothing indicates BB was even going all out at any point. He holds back a lot.
BB being a lot stronger than Aokiji, and Bb being a good leader is enough for Aokiji to be an underling.
Even Oda said he would want to join BB pirates if he was strong.
Blackbeard showing against ray
- Rayleigh: its 2 v 1 with Hancock, not even 1 v 1 and needed to get his stone commanders back as well, instead of fighting Rayleigh+Hancock, he choose to accept Ray's offer if they are actually going to give his men back or not, and they did, if they didn't he was going to fight both at the same time anyways.
Considering how unreliable BB is, instead of finishing BB there and not giving BB's men back, would be a better option for Ray and Hancock especially when Ray also said he doesn't like BB, but Ray admits he + Hancock couldn't win vs. BB in 2 v 1, so they gave his men back.
And not only he takes his men back, he even kidnaps Koby while S-Hawk and S-Snake was also there.
- Law: Law was retreating and he was forced by BB to fight, Law couldn't even retreat vs. BB due to the power difference.
BB's power is simply above Kizaru, Aokiji or Red Dog.
Law has the best chance vs. BB due to his abilities being suitable for surprise attacks, and has the best 1 hit attack power compared to Kid or even compared to Luffy, and BB usually gets hit due to his overconfidence at the beginning of the fights so Law is actually a bad match up.
And Law surprised him with awakening and still BB took it with as same as Big mom who is known as durability freak. BB also has a better attack power than Big mom.