Man why can’t Sawamura just do well as the ace!? I know he will be able to prove himself...

I agree with the frustration but I also understand why it happened.
First time starting an official match being the ace for the first time in their first game that decides whether they make it to the next round or not, and wanting to meet expectations from the get-go.
Not to mention that even if he was wearing the ace # and his teammates were happy for him, they still in a way treated him as the usual Sawamura, so seeing him put in that effort and come up short because Miyuki wasn't able to lead, batters weren't able to get adequate runs and the build up pressure, changed their perception of Sawamura and truly saw him as someone that carried the team
Okay long reply sorry

Miyuki couldn't lead? When was that? I don't think that's true at all. Miyuki has never failed in gamecalling. He was impressive when he felt so terrible about Sawamura having a bad first ace experience. That's all.

Well that the point tho, they have mentioned it before the only way to show that the game calling and catcher's lead is correct is by getting outs and making the pitcher shine and pitch to the best of their abilities. In this case miyuki mentioned that he couldn't do those things for Sawamura

without looking it up, I believe Miyuki said that he wished he could have been more help to Sawamura. I don't know if you know this, but in RL baseball there's a near 100% consensus that the catcher's job is by far the most difficult job in the game. The sheer volume of information he has to retain and keep track of is almost endless. There's more to it than just blaming the catcher's gamecalling for everything including the failures of the pitcher. Not even Johnny Bench could have made a pitcher shine if the pitcher was throwing nothing but balls.
When they say "shine" they mean that the catcher should encourage the pitcher, try to improve his self-confidence by talking to him, give him positive feedback when he throws a good pitch. The catcher can't work the pitcher's arms by remote control.
Gamecalling is a lot more than taking care of (babysitting) the pitcher.

Gamecalling is the catcher's decisions based on him keeping track of a huge amount of input that he processes in a split second. He has to be aware of everything happening on the field at all times, particularly the strengths and weaknesses of the hitter, not just the pitcher. If I tried to list everything the catcher bases his next call on, I'd probably run out of space here.

I looked it up. Miyuki didn't say that he failed to lead. He would not, could not ever say that. He is the leader, the general, when the team plays a game. In the first season, do you think the captain of the team is the leader during the game, no. Miyuki is, and Yuuki has to do what Miyuki tells him during the game.
There's a reason the story keeps emphasizing Miyuki being an amazing player. It's not because he hits homeruns, or because he does a good job of catching whatever the pitcher throws at him. Those things count, but there's so many more important skills he has that will make him a number one draft choice.
You're missing out on the fun if you think those pages in ch156-159 are about Miyuki admitting to doing a bad job. He didn't. Those pages are to pull at your heart strings about what a kind, empathetic, amazing person Miyuki is. LOL they're character development to the nines.

Maybe I didn't word it correctly or was too vague, essentially there were a lot of built up factors that led Sawamura to pitch poorly in his first game as ace and to me its honestly not surprising nor was it out of nowhere. I was actually referring to what he says in chapters 154 & 159 he is a great catcher but he wasn't able to pull Sawamura's best pitching, and they have mentioned before that the only way to know if a lead is right or correct are the results. I know a catcher is much more than that and miyuki carried the role of captain and 4th batter to boot, he wasn't able to get Sawamura out of his struggle but he tried making it up and prove something with that homerun, hence their dialogue right after it.
I totally enjoyed and loved the character and team development (especially the coach's) that was shown but it would have happened without the various factors that lead Sawamura to be taken out of the game.

thank you for such a nice reply. Yeah, I really like it, too, and didn't even notice on my first read through that after Sawamura got switched, for the rest of the game Miyuki looked either furious or upset, and it turned out to be him shouldering half the responsibility because they are a battery when they pitch and catch in a game etc. I guess Miyuki would take that very seriously. That line about "the ace is not alone when it comes to carrying the team" which he said to Sawamura right after the homerun was a killer line, and he even had his hand reached out toward Sawamura . It was really sweet.
I find catchers to be fascinating more than any other position in baseball, so I tend to be partial. I liked it how hard Miyuki kept working so hard to get Norri back on his feet.
I think Coach Kataoka had a big failure during his first game as ace. I think that that Coach Sasaki talked about it and compared kataoka to sawamura.

The new first years are crazy about Sawamura and very impressed with him, which is cool and good to see him getting some people on his side.