Yes, Luffy's Gear Five Is in 'One Piece Film: Red'
On this occasion, fans can also get the clearest and most complete look at Luffy's mysterious new form. Gear Fifth indeed turns the Straw Hat captain's clothes white, except for his blue/purple sash.
Since Luffy's Devil Fruit is actually a Mythical Zoan instead of a Paramecia, it granted him a completely new transformation instead and typical of Luffy, he ended up naming it Gear 5. In this form, Luffy gains a completely white transformation and takes on an appearance similar to that of the "Sun God" Nika.
In the final battle against Kaido in Wano, Luffy awakened the powers of his Devil Fruit and acquired a new form, Gear Fifth. He uses that transformation briefly in One Piece Film: RED too, but there are a few conflicting elements that make it difficult to establish if the movie actually takes place after Wano.
Gear Five's color changes were somewhat elaborated on in Chapter 1045, "Next Level." Yamato described Luffy's hair and clothes as having turned white. Kaidō described the form as pure white. Both of these can mean different things, but they at least made clear that Luffy's new color scheme is primarily white.
Nika is said to bring smiles and freedom to the people. Likewise, Luffy is given complete freedom in his Gear 5 form and is always seen laughing/ smiling. Since Luffy is now an awakened Zoan devil fruit user, he has grown mightier in strength, moving at a god-like pace and his toughness too has become unbreakable.
The more he laughed, the better he seemed to fight. Throughout the clash against Kaido, fans could see him laughing even though he was fighting a high-intensity battle, which just goes to show how important it is to his character.
1) Kaido. 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.
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.
Of course he can. In base even. You see throughout the whole fight that Luffy is playing with Lucci. Lucci is not able to land a hit on Luffy and due to the nature of Gear 5 he is way more playful and jokes around with his enemies.
The concept of power up Gears has been a core part of the One Piece franchise and allowed Luffy to take on the most difficult of foes. Fans speculate Gear 6 is inevitable – and with the series winding up to its conclusion, it could play a pivotal part in the final conflict.
Gear 10th Luffy is Luffy's ultimate form from the upcoming speculative fan-made sequel to One Piece, Son of the Pirate King. Luffy has continuously trained his haki and Devil Fruit powers during his time as Pirate King until he achieved this gear.
Although Luffy calls it Gear 5, it is actually the awakened state of his devil fruit. In the “Wano Country Saga,” fans learn that Luffy's devil fruit is actually a mythical Zoan type having the properties of a Paramecia type.
In the anime, some Haki users are shown surrounded by different color auras (such as red for Luffy, purple for Doflamingo or pink for Big Mom) even if they are not using Haki at that moment.
It looked like some type of demonic aura emanating off Luffy but in any case it mostly likely Haki coming off of him with his rage.
His hair and clothes (with the exception of his signature straw hat, belt, and sandals) turn white, his eyes glow with red ring-like pupils, and white clouds float around his neck, similar to the clouds of steam that accompany him in Gear 4. His eyebrows also become swirled and billowing.
Roger and his men, as seen during the Oden flashback, would simply be too strong for Luffy to defeat in a fight.
When it comes to destructive power, Saitama can destroy giant spaceships, monsters, mountains, etc. with the bare minimum effort. Bearing in mind Saitama's feats, Luffy's Gear 5th stands absolutely zero chance against him.
Pitted Against The Navy's Strongest
In this case, it is safe to say that with further mastery of Gear 5, to negate its drawbacks, as well as a bit more proficiency in his use of Conqueror's Haki-infused attacks, Luffy should be able to defeat the two Admirals by the end of the story.
I don't think you can simply say "he can beat an admiral" because even within the Admirals, there's such a huge difference in power. I personally think that Luffy could probably just barely beat Aokoji now (or in the near future), and he could fight but not beat Kizaru, and has no chance of beating Akainu.
Mihawk is said to be close to the same level as Shanks and is even dubbed as the greatest swordsman, so to say Luffy would defeat Mihawk is still debatable in the eyes of many fans.
1) Marshall D.
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.
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.
So, for you manga-readers: yes, Gear Five is in Red.
He does not smile for quite some time following his victory, because he continues to go through troubling situations. Four episodes pass until he finally smiles again, once he makes a "safe" landing on a building with Nami after using his Devil Fruit powers to trapeze through the air.