That Shanks/GB interaction gets way overwanked lol. GB was always overexpressive, he is the same guy who sweated at Yamato in one panel while getting no damange from an Advanced CoC attack from her and easily restricting both her and the rest of the Scabbards at the same. They literally looked a neg diff for him while being all together lmao.
Furthermore, GB had just pulled up solo against an alliance that defeated not one but two emperors. If a whole third party like the Red Haired Pirates appear as well acting antagonistically towards him, being intimated is a fair reaction lol. Heck, he even said: "I'm not ready to pick a fight with you guys yet."
People also bring up Kaido and how GB didn't pull up on Wano while he was there, but they sure as heck don't shit on prime WB for also not going there. And WB had far more "personal" motives to go there, his "brother" Oden. And mind you, folks are right not to dowplay WB for that. It's not a hit on his portrayal. But, for some reason, the same doesn't apply to Greenbull. And Greenbull is a Admiral, who specifically need permission to attack/fight in Yonkou territory.
Nah man, the GB downplay has been wild. He's a monster strenght wise.