'Aishiteiru to ittekure' is one of my favorite j-drama of all time!!
The story, the characters and even the actors were so much better, But I got really similar vibes from these shows -
The similarity was mainly with the lead couple's age gap, their overall chemistry, the 'teacher's student' trope and the setting of the story.
I feel like if you have seen one of these series, Chances are you will also like the other series.

same director!!!! u welcome !:)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))

I think The style in both films is similar but ''hush!'' has more significant themes.

in both films Two guys are involved with a woman who is looking for love and meaning to her life, with many difficulties and problems that accumulate in their way, they find solace in the friendship that is formed.

Personally I didn't really like Kira Kira Hikaru, but if you are looking for a better and similar movie then I recommend Hush!

A group of friends, two of them a gay couple, one girl who connects with them in an eccentric, sudden and platonic way.
Fate connects the three and creates a connection with the theme of love and friendship.

Shuji Ito is a shy boy in the top class at secondary school. He feels attracted to his classmate and best friend Yoshida , who is not aware of Ito's intimate feelings. The two spend time with Kasane Aihara who is a new student in their school.

In both the series and the film The three characters make a bond with the theme of love, intimacy and friendship

The story, the chemistry between the characters and the location in the school are very similar to this story, the atmosphere in general are giving the same vibes...

If you liked the series you will also like blueming.
The circumstances in which the couple met each other are really similar, also
the stylistic tools of the director are similar.

The chemistry between the couples are really cute and bubbly

Personally, I liked blueming more, but that's just my personal opinion

It's a bit hard to explain... if you like the enemies to lovers trope, you'll just love this series.
another similar point - the series focuses on two high school student, one of the characters likes to study and is good at it and the other causes problems.