Bellamy doesnt matter.
Luffy is beating people, yes.
With countless punches, through damage accumulation.
Garp can beat people too, through the same damage accumulation.
He aint anywhere close to beating Kuzan/Shiryu with one punch.
Meanwhile he ended up losing due to Shiryu's stab for Coby...
Bellamy does matter.
Kaido also used a blunt attack even if he was using a weapon.
Katakuri also went down after a couple of punches.
Cracker whatever the hell that "attack" from Luffy was.
Never said Garp was one-shotting Aokiji or Shiryu. And while Shiryu probably badly hurt Garp with just one slash that didn't took him down and he was fighting several people at once receiving damage from other sourcers too(at least from Aokiji it was confirmed).
I don't know what your point is? Garp is clearly beating Teach's crew all by himself until that stab from Shiryuu that has an invisibility DF. Not just pushing as Marco did but badly hurting all of them. Maybe he couldn't defeat one but for sure he damaged them and handled so others could escape.