Prior to this, Saitama commented that they were both "having fun", and afterwards neither fighter was in the least bit strained
Does Saitama say they're having fun - somehow denies that they're not holding back? They can use all their strength without holding back. It's okay to have fun about a fight where you put in all your efforts and where it is difficult for you to defeat the enemy. Saitama is waiting for such an enemy.
By the way, it is Saitama's statement that can confirm my words. Saitama believes that a fight from which you can get a lot of emotion and pleasure is one in which both fighters fight on equal terms, using all skills. Fear, excitement, adrenaline. This is what Saitama believed throughout the manga.
amming links of the same 5 second clip does not prove that Garou was taking it seriously, when moments later Garou states that it's time to "kick it up a gear"?
Garou never yells or makes an aggressive expression during a fight if his enemy is much weaker than him and if he is holding back in a fight. On the contrary, if he attacks an enemy weaker than him, then he tries to defeat him as quickly as possible. None of the heroes who were much weaker than Garou could react if Garou launched an attack because he was not holding back. He showed that the enemy is much weaker than him only when he begins to simply dodge the enemy's attacks (Golden Ball) and does not attack, thereby showing that their difference in skills and speed is completely different. He was calm even during fights with Tanktop Master, Bat and so on. During their fight, he does not scream or tense, because he believes that defeating them is easy (Because he is much faster and can repel all their attacks).
But as we can see, Suiryu successfully blocks Garou's attacks and dodges them.
The fact that he screams with effort and effort is proof that Suiryu is forcing Garou to prove himself.
But Suiryu holds back, even if the enemy is very strong. When he really uses his best, he starts to fight very aggressively, his muscles get bigger, and his behavior, as I said, becomes much more aggressive.
Garou's last line tells us that he is going to put in even more effort. If a person really does not hold back and tenses during a fight, then this does not mean that he is physically unable to show more effort. But it also does not mean that before that he held back. Human still used a very high threshold of his capabilities, not holding back and screaming during attacks. And later, he can still use his FULL potential, using the maximum possible force and attack speed that he can. But as a rule, it exhausts people and spends a lot of energy.
So this does not mean that if Garou, with a little more effort, was able to cause a bug due to speed, then it means that he is much faster than Suiryu. After all, of the two, only Suiryu could truly completely restrain his powers.
Garou's final hit was the only one that caused the bug because it was slightly faster than past hits. Conventionally, this program can have a speed limit of, say, Mach 65. Garou could fight at Mach 60-64 throughout the fight. So we cannot claim that the fact that the final blow could not be recorded by the program is evidence in favor of the fact that Suiryu cannot scale to Garou. Moreover, during their fight, as it turned out, Garow did not hold back and put in great efforts. He even used Water Stream Rock Smashing Fist, lol. Garou only uses this technique in serious situations when the enemy is really dangerous and can defeat him. But Suiryu held back, because he did not use his best fighting style. The program still, in theory, could not have time to record his movements, if he ceased to restrain himself.
By the way, even if Garow was holding back (which is not true and nonsense) - would he hold back the speed of his reflexes? He might have held back the speed of his punches, but he wouldn't slow down the speed with which he responds. And as we can see, he missed Suiryu's kicks on the head. This is stupid, no one does that, why specifically give yourself a hit, especially in a video game in which your AP and durability do not matter, because your avatar has its own HP bar? Garou may have a silly and childish motivation, but he's not dumb.
And in general, during a fight, the speed of blows fluctuate. It can be in people as 10 m/s, and 9, and 12, and only sometimes it is 14 m/s. But this does not mean that the person held back in a fight before. It's just that this time he accidentally managed to hit a little faster.