Kaido did in fact lose to Luffy's Gear 5 at the end of the Wano Country arc. However, keep in mind that he withstood multiple waves of strong enemies before this final encounter. Luffy was also completely worn out after the fight and fell into a coma for about a week.
Is Luffy Gear 5 the strongest? Yes! Of course, Luffy's Gear 5 is the peak of his colossal powers. He can literally do ANYTHING with his devil fruit powers right now, as he transforms into the Sun God Nika when using Gear 5, making his devil fruit the strongest in existence so far.
Luffy defeating Kaidō has been one of the biggest milestones of his career as a pirate. It officially made him one of the Four Emperors and established him as one of the strongest living characters in the world of One Piece.
Luffy is close to Shanks in terms of power and it is only after their fight that he will officially be able to call himself stronger than Shanks.
so I do believe Luffy is more than capable of fighting in feeding an admiral. but that doesn't mean this fight won't take both these guys to their absolute limits this will be a very difficult fight on both sides you know that battles in one piece could get very unpredictable.
Bearing in mind Saitama's feats, Luffy's Gear 5th stands absolutely zero chance against him.
It is a known fact that Kaido has lost to his fellow Yonko and the Navy a combined 7 times and been captured a total of 18 times. While Kaido might be the strongest in terms of raw strength, there are definitely those who can beat him a fight. Write for Us!
In this formidable show of strength, we are at least made known that he was defeated 7 times, and captured by the marines a couple of times as well.
While the effects of this technique have been mitigated in post-time-skip One Piece thanks to training, the prior uses have already caused irreversible damage to his body. Luffy dies from gear 5th strain on his heart and law gives up his life so they can win. This causes Luffy to go into gears without dying.
In addition, Luffy still has his standard weakness to cutting attacks.
One Piece's most recent chapter confirms that Luffy can now actually manipulate reality, as shown in his battle against Rob Lucci on Egghead Island. One Piece fans were in for a major shock recently when the series confirmed that Luffy can manipulate reality thanks to his Gomu Gomu no Mi awakening, Gear Fifth.
It is evident that the only person capable of surpassing Roger is Luffy. Even though Luffy still has a lot to achieve, he is the only person who can transform the entire world.
Blackbeard is arguably the biggest counter to Luffy's Gear Fifth. Most characters can only hope to survive it. Meanwhile, Blackbeard can just cancel these Devil Fruit powers with his Yami Yami no Mi. Cartoony physics is a very broken ability in the One Piece series, but it has its limits.
Even without Gear Fifth, Luffy is still a master of various Haki techniques. Sabo is yet to display the same level of skill as Luffy did. This could potentially change in the future, but even then Sabo isn't nearly as durable as Luffy.
Before awakening his Conqueror's Haki, Zoro wasn't even as strong as a top Yonko Commander, let alone a Yonko. Although he did fight Kaido and even managed to earn his praise, which is quite impressive, it was pretty clear that Zoro wasn't anywhere close to him in terms of either power or skill.
Also renowned as 'Garp The Hero' and 'Garp The Fist', Monkey D. Garp is a Vice-Admiral of the Marines. Being their strongest known member in history, there's no denying that Garp is capable of taking on Kaido.
Yamato was capable of holding back Kaido and that's all an Admiral has to do. Kid and Law took down Linlin, two Admirals would decimate her. Once that happens, Three Admirals at the same time vs Kaido would destroy him in a minute. Admirals also has greater teamwork than two yonko.
Chapter 1040 saw the momentous defeat of one of these emperors, Charlotte Linlin, better known by her epithet "Big Mom". Big Mom's defeat by Luffy's allies (for the time being) Trafalgar Law and Eustass Kid, has major implications for the future of One Piece.
Oden is the first person to gravely injure Kaido and fight with him on an equal level. Though Oden suffers defeat, he is by no means weaker than Kaido. Oden would have definitely won against Kaido if not for the deception.
He even fought against Captain Rocks on God Valley. Garp may be old right now, however, he is still more than capable of taking on Shanks in battle. This is evident from the fact that he recently set out to fight not just Blackbeard, but his entire crew on his own so as to rescue Koby from the grasp of the Yonko.
Could Gear 5 Luffy beat Big Mom with all of her powers at her disposal? Yes, he would. Kaido already indirectly stated that pre Gear 5 Luffy was > Big Mom.
Goku would easily be able to combat the Jump Rope technique through his alien durability and has been depicted moving mountains far heavier than Luffy's stretchy kaiju form. The main reason that Gear Fifth can't beat a Saiyan is because Luffy's abilities are still growing and have more potential to be unlocked.
1 Gomu Gomu no Bajrang Gun
Bajrang Gun is, by far, the strongest technique that Luffy has developed in Gear Fifth so far. This technique sees and makes use of everything that he has got. While using Gear Fifth, Luffy creates a fist big enough to dwarf an entire island and retracts it just like he does in Gear 4th.