Manga heavily disagrees with you on this one, Garp tanked nothing compared to Whitebeard
Each character has his strengths and weaknesses
yeah
WB has great power
Kizaru has great speed
Roger great haki
Etc etc etc
But it doesn’t mean those stats are wide wide apart
Top tiers are top tiers because they can fight each other. They are overall close enough for them to have a fight.
Garp is among the strongest top tiers.
‘Is Kizaru faster than Garp ? At full speed yeah it’s likely. Can Garp fight Kizaru and somewhat react to him with speed and haki ? Yeah totally
and that means that Garp scales to Kizaru speed wise. If you think Kizaru is light speed then Garp is light speed or close to it. Because he can fight him without being blitzed like a bum.
You can think WB endurance is greater than Garps, why not. But are they relative in endurance yeah. Garp fought Roger, Xebec and Shiki. So Garp can/could take top tiers hit and carry on. Either with his haki, or strong body or willpower etc.
‘So Garp scales in endurance even if it’s lesser than WB.
Same for AP. Garp scales to the top tiers of OP and especially scales to the strongest guys because he fought them.
Even if I disagree you can think BG would overpower Garp strongest move ever. But it won’t neg diff it and there will be a good clash. So it scales
Marugori is toasted here