Anyone have suggestions for manga where there is an age gap between love interestd, similar to me cinderella or takane and hana?

Taiyou no ie. Maybe. They have age gap

I just came across a review on ANN today that talked about the age gap element Cutie and the Beast. It sounded like a good story.

Living no Matsunaga-san felt really fun and fresh.

A few of Mika Yamamori's works feature this, like Tsubaki-chou Lonely Planet and Hirunaka no Ryuusei
Spoiler for the end of Hirunaka:

I don't think she ends up with the teacher, but he's an important romantic element.

Nenene is a very charming one-volume one.

There are also plenty of student-teacher ones, such as Shiota-sensei to Amai-chan and Faster Than a Kiss (imo a mid-2000s classic, haha).

I recently read an ongoing manhwa I Found Somebody to Love It’s around an age gap of 10 years. The pace and structure of the story could be a little better but the story is decent, but more importantly, as an age gap, I felt the maturity characterisation for the older lead is spot on.

Its josei and has a serious tone and not a lot of comedy , and it also explores a number of real life literature works (the male lead is a lit professor and the female lead an almost graduating university student) so it’s somewhat a slow, thoughtful read. See if you like it.