He's not protecting the plot, is just that the author write things in a way that Souta decision ends up being the correct one.
In the beginning, he chose to not interfere with the Hero's team (because of the plot) and thus ended up managing to avoid Tsukishima's attention.
In the Exam, he went...
He's not doing that to save the cast if you pay attention to what Risa said eariler he was the one who sabotaged E class and did nothing on the exam either. He's doing that to impress Kaoru and build his own harem. He doesn't give a rat ass about his classmates.
Unfortunately, Kaoru is the mangaka favorite heroine so she's not going to cuck Souta or show any sort of interest in another male character, I think it's obvious.
Also, I don't expect Souta to romance the other heroines as well.
It's the mangaka choice to give focus on them, in the novel they don't show much because we see more focus on Souta's adventures. Mangaka sacrificed those to write an original story with the hero's party and give them character development.
That's the problem this whole segment was skipped by the mangaka and he decided to add original stuff and write more about Kaoru and Hero's Team.
The entire Bloody Baron Boss he fought with his sister was skipped. And farming with Risa and Satsuki too.
Chapter 50 and 51 are both ready but since some people complained about the translation on ch48 thread I'll take some time to revise the text for those next two chapters.
I'm using gemini and other translators, but really page 3 give me some trouble, but it's mostly an English problem than a JP to ENG I wish I had someome to proofread it for me.
Looking at the release, I reached the conclusion something is missing, I guess the image size is not at a good size. Tomorrow I'll release 48 and 49 with 200% scale that should reach the same size as the late Surya releases.