Chikasugi! You’re Too Close Again!! - Oneshot

[NARESH4444]

Why would you want to serialized? You KNOW what will happen.

introduction: super serious teacher strict with anyone but dead on the inside, bonus if there is a friendly female colleague that makes him notice he won't ever make friends if he keeps acting like that.
Notices Gal wearing sloppy dress, she teases him, tells him if he wants to look at her or grope her out of nowhere
repeat the formula of "perverted gal who is also a virgin that teases and embarasses him, with occasional ecchi" for....20 chapters
flashback to her as a young girl, connection with him, maybe he was kind with her one time.
He slowly realizes his feelings.
Big Timeskip: waiting for her to become adult or he is getting transferred, or she is getting transferred.
they meet again, hug, the end.

Boring, the writer should have set it in university.
But if you really must then read something like Kuro Gal-san ga Kuru!

Or...

He's not dead on the inside,just serious.
He appreciates other females just isn't trying to woo them.
However,due to the one student,his thoughts are filled with her,which actually results in him not seeking anyone.
She herslf might've been a straight laced loner who saw the light when he helped her with something small the previous year,and then changed herself to a format that would most work against him.
She,of course,is going to far with the offensive,making it seem like one-sided teasing.
She gets flustered when other females show actual interest in him,more those of similar age.
He slowly realises that she is genuinely into him and eventually they agree to being a serious thing after she graduates.
On the say she does,she pulls a "Tawawa On Monday" against him.
The epilogue shows them dating/engaged/wedded/as a family.

It's not boring since what you typed and what I've typed are just two of the results,there's literally hundreds of other ways this can pan out,depending on the comic its' in,the reception it receives,how the author plans it out,and the pacing.

You don't need it set in university levels to get good results,you just have to use the tropes effectively.