SPOILERS AHEAD

Hitorijime My Hero is a spin-off to the manga Hitorijime My Boyfriend. While its parent focuses on the back story of Asaya Hasekura and Kensuke Ooshiba, the more popular spin-off focuses on them on the sidelines, along with the relationship of Kousuke Ooshiba and Masahiro Setagawa.
The story largely revolves around drama, I incurred, tho there is a sufficient amount of romance as well.
The story is about Masahiro, a delinquent taken in by the Ooshiba family consisting of younger brother Kensuke, older brother Kousuke and their mom.
#Overall Plot and Pacing
Now the story has pretty fast pacing I'll tell you that much. The manga has terrible pacing and lacks quite a lot of details, making the plot go by too fast. That, however, is kinda fixed around the middle, so it's not that bad.
In the beginning few chapters,

Spoiler, click to view

I think around 8 chapters in, Kousuke had asked Setagawa out, they had the conflict with Tooru and his gang, and I think even exchanged rings etc

It was a lot for just 8 chapters. The story was interesting tho so while reading, I didn't mind too much. But I was very confused about the rest of the plot as I had watched the anime first, and I had already caught up to most of the plot from it in around half an hour.
#So what about the rest of the manga?
Well it mainly revolved around the daily life of Setagawa and Kousuke, with Kensuke and his friends from school. Some new conflicts were introduced, which were interesting enough, there was a lot more development between Kensuke and Hasekura's relationship, which I wasn't expecting at all, and it was quite lovely to see more of them as well, I really enjoyed seeing developments in Hasekura's personality.

Spoiler, click to view

There's developments about Natsuo and Yunge, two vague characters in the anime but they get a lot more screentime around the middle of the last volume

Problematic Points

Now Hitorijime My Boyfriend was based around the relationship between two childhood friends of the same age.
However, Hitorijime My Hero is a relationship between a teacher and a highschool student, with an age gap of 12 years. Masahiro being around 15 when they start dating. I personally didn't have any issues with this, given that I've seen stories like this where the younger love interest was too young to be influenced. Here, I can kind of feel at ease with Masahiro being more mature and showing more independency towards his relationship, including the decisions he makes.
There's still issues like

Spoiler, click to view

Kousuke kissing Setagawa for the first time, or him trying to provoke Setagawa to come clean about his feelings

Look if you're gonna read this, you would need to be open to the age gap or it will be a very uncomfortable experience. I'm not saying the manga showcases age gaps well, but if you're uncomfortable, then just don't read it, is what i mean.
The anime might be a more comfortable experience because the manga is quite explicit at times. It doesn't really show anything but there's a lot more sexual implications and scenes, whereas in the anime, it was all like a second long and only showed their faces.
Masahiro gains a lot more sexual independency towards the end so there's a lot more ecchi-like scenes. Please be wary of that.

#Conclusion

For a BL lover, the story is actually decent, it's worth a read, only worth it if you can bear the age gap. The art is also very pretty, the characters are super likeable as well, so you would probably end up feeling sad about not getting more chapters if you really got into it.
People liking it or not will definitely depend on preferences, it's not an easy subcategory to enjoy, I understand that.