The issue is that :
-He wanted a warship then runaway from Akainu without the warship
-He wanted Boa’s fruit then runaway from Rayleigh without the fruit
So if he does not achieve his primary objective once again this will dehype him a great deal imo.
Then you didn't get his character bro.
He wanted warship but he wasn't expecting Akainu to come personally. Fighting Akainu just to get warship isn't worth it in his eyes. It's more to lose than gain.
Yes, he wanted Boa's fruit but Boa turned his crew into stone. And, Boa herself said, even if BB gets her df, his crew will remain stoned and only Boa can undo them.
Was getting one df worth more than sacrificing the crew members with dfs he collected for almost everyone? No
He isn't coward. He isn't hot headed generally. His character is about assessing pros and cons and if cons outweighs the pros then he won't hesitate to back away