Gaban, like Garp or Rayleigh, may be able to trounce a Yonko for 5-10 minutes max
Putting one down for good is not happening. Gaban gassed out after putting his all into avoiding only base Luffy, who wasn’t being serious enough to block for himself because he didn’t take the old man seriously. The only major older man that Luffy has ever met that he didn’t say “wow you’re strong”.
Harald = strong
Fujitora = strong
Kyros = strong
Kizaru = OMG strong
Loki = OMG strong
Gaban = “waste of time” “talks too much”
(this post is satire, fuck Luffy)