It's actually the opposite.
Garp is not only super strong, but he used a big brained move by sending Kuzan flying underground so that can buy him some time to whoop the rest of the BB pirates very fast. Issue is Coby was a liability, but Garp knew he would have to either:
1.Take cheapshots from the BB pirates while focused on Kuzan
2.Leave his fodder gang to the BB pirates
Instead he dealt with all situations with one big brained move. He got to focus on the BB pirates with Kuzan out of the picture, and he got to ensure Coby survives, then he got to focus on Kuzan again once the BB pirates were scattered.
What a chad honestly.