Well, considering that all my posts are stating that Yamcha seems to be presented as being way beyond Shang Chi in terms of speed and strength, I don't think that I'm particularly interested in making that argument. My point was that, as Yamcha himself stated during that fight, Kami got a bit too arrogant and wasn't straining himself at all, which is why he was standing still and got hit in the jaw by an attack that unexpectedly came up out of the ground.
I mean, the fight went:
Kami pretended to be some nebbish middle aged man named Shen who was randomly flapping around and being casually dodged by a Yamcha that was trying to humor him, only for Yamcha to get the wind knocked out of him when Shin "accidentally" fell over in a way that ended up with him kicking Yamcha in the gut. Then Yamcha tried to gently kick Shen out of the ring only for him to panic and duck, "accidentally" causing Yamcha to ram his crotch into Shen's skull and roll around in pain for awhile. Then Yamcha gets laughed at by the crowd but still tries to play it off as not bothering him, until Shen commented about how he was definitely going to win and got Yamcha a bit irked so he got into a prepared stance and told Shen to attack whenever he was ready, resulting in Shen instantly elbowing him in the face hard enough to send him rolling across the ring while Shen waited around for him to get up, which took a few panels, and then chided Yamcha about not noticing the subtle movements in his form that should have warned him that he was only pretending to be a novice.
Following that, Yamcha went all out and got still monstered all over like a n00b while Shen casually offered tips and kept up a stream of compliments about Yamcha's skill and potential to surpass even himself sometime in the future. Eventually, he confided that he was actually just possessing the body he was using at the time (though at no point does he imply that doing so made him any weaker), after which Yamcha charged up the Soukidan without Shen doing anything except commenting on what Yamcha seemed to be doing. Now, when Yamcha finally fired it off, the speed definitely seemed to impress Shen/Kami, but he still dodged it twice, with the second time resulting in the attack apparently being "accidentally" buried in the ground and Yamcha complaining about how fast Shen was. Then he admitted that he never dreamed that Yamcha could do anything like that and Yamcha revealed that he had been faking his previous ire and caused the attack to fly up out from underneath Shen's feet and suckerpunch him in the jaw, which shocked the entire crowd.
This was then immediately followed by Shen/Kami flipping in mid-air so that he landed on his feet and immediately one-shotting Yamcha in the gut hard enough to make him stagger backwards until he fell out of the ring. And in Shen's next fight, he opened up with an attack that instantly blew up the ground underneath Piccolo's feet and dodged an energy beam that went way out of city limits in moments and proceeded to make everyone else who wasn't Goku practically soil themselves with how much power and speed he was showing.
So, yeah, he landed a hit on Kami, and it was depicted as being subjectively super impressive by everyone, including Kami himself, and is way beyond what most people in DB Earth (much less Shang Chi) could do, but there is a big green asterisk on the feat from an objective prospective since it was only possible because Kami was holding himself back immensely, didn't go after several major openings so he could give Yamcha a lesson, allowed him to charge and fire the attack off in the first place, and then let his guard down to compliment Yamcha instead of seriously going on the offensive. And the moment that he did get serious, he won.