The main advantage wasn’t his blunt force immunity, Kaido uses a variety of attacks fire, slashing, haki and none of it worked. There was no “main” advantage of G5 the form offered a lot and all of it played a role in the victory.
Gear 5 damage isn’t lower the Gear 4. The intro to g5 stated that Luffys strength was increased. Zoro isn’t top tier yet if he is he’s the weakest top tier there is. Everything you said is false.
You realise your first paragraph made no sense right?
"The main advantage of G5 wasn't blunt immunity"
"Kaido tried every attack in his arsenal and none of them worked"
Why didn't they work? Because of Luffy's blunt immunity. All of Kaido's attacks are garbage outside of his club attacks and Blazing Bagua, ergo, Luffy negated the
vast majority of Kaido's moveset. This is not up for debate.
It stated Luffy's
physical strength increased. That means nothing in terms of its relation to G4's AP, which increases AP through haki and spring force. So idk what your point is. Fact of the matter is the strongest G5 attack is an imitation of G4.