The punch wasnʻt JUST from chakra in the seal, itʻs from her downward momentum from her jump. Based on what can sakura focus more chakra into her punch than what weʻve seen in the manga?The punch was from the Chakra from the seal the more Chakra is focused the stronger the strike seeing she released the seal worth 3 Years if Chakra.
Sakura didnʻt even know how to walk on water at the time of the chuunin exams. Ninjas in part 2 by default amplify their speed with chakra since they are all at the level of adept chakra control in order to enhance their physical abilities. If Sakura could amplify her speed with chakra way back chapter 80 ish, then sheʻs obviously always amplifying her speed with chakra now considering how much more adept she is with chakra. Therefore sakuraʻs greatest speed feat is sakuraʻs greatest speed, and she doesnʻt blitz naruto with it unless you believe that sheʻs far faster than V1 Ei or sandaime raikage.Ninja's do not Amplify there speed with chakra by default very wrong.
Sakura in the Chunin exam was able to blitz Ino who was 2.5 ahead of her in the speed department.
yet she canʻt do that if she has to jump first. And then she destroys the clone with the shockwave, blinds herself with the dust cloud and gets ended by a FRS from the real naruto.By the time he sends a clone to fight her(Close-Range) she wouldn't even need a direct hit to kill him seeing he would get caught up in the radius of the punch.