BB is downplayed because he has power but is easily intimidated. He ran from Shanks. He ran from Akainu. He crapped his pants when Rayleigh showed up. Battles are won in the mind as much or more in the body. BB lacks conviction and courage. On the flip-side, BB might figure that Pyrrhic victories aren’t worth the losses. Pick your poison
If a battle won in mind and as much as the body BB choses what best for him ( dude was going kill Boa and his crew members cause he was at disadvantage )
Even if he had WTF face with ray he still up with the better end of the deal since BB could do what ever he want to hundreds marines and got his crew members back lol .( taking koby to try be king in one reason i like BB he always working at something )
BB scar shanks but at MF he just don't think fight was worth it and that was coming off fighting sengoku and Garp so he was fighting like everyone else.( to me that perfecct eg of picking your battles same with Akainu )
People can say he crap pants or is look scared etc etc but i think that part of BB charm but man know what he doing even if he acts that way .
Even with everything you said about him , BB now almost as close to luffy in finding the OP and now has garp as a bargining chip.
I don't think he lacks conviction ( courage more debatable ) yeah he sneak attack law but that could have been kid or SH so he was confident that he could win with not even his full crew who ever show up.