Bro. No one ever said Celestial Dragon Shanks doesn’t live by his own rules lol. It’s just that his own rules include being a Celestial Dragon dog and a high ranking member of a slave bearing organization. Little Figarland doesn’t need to keep close connections with the Gorosei but he does anyway, actively asking them to take out his rivals. Lol
And this is why the Admirals can’t attack him, because he is a Celestial Dragon whom the Admirals protect at the threat of the death penalty. Aramaki even wants to get Little Figarland’s protections lifted so he can kill a Celestial Dragon with no consequence.
Why do you think Sengoku says “I’ll stop the war because it’s you.” He knows he won’t get in trouble for sparing a Celestial Dragon from death lol. In fact Sengoku was probably concerned that the Holy Knights would execute him if he killed Celestial Dragon Shanks.
Celestial Dragon Shanks’ life as a pirate is pretty meaningless tbh, it’s easy to accomplish the shit Celestial Dragon Shanks has when the Admirals are protecting you. Lol