The girl in Oresama Teacher is smart WHILE FIGHTING. And that's it. Otherwise, yeah, she's pretty ditsy. I don't know if I'd say straight up stupid, but she's a smart fighter, outside of a fight, she's better relying on the judgement of others. 2c3m43

Also, my suggestion would be Akagami no Shirayukihime Lead female is a healer who stands up to her oppressors and is an equal with her love interest as far as personality goes.

Yume no Shizuku, Ougon no Torikago

“The mind is its own place, and in itself can make a heaven of hell, a hell of heaven..”
― John Milton, Paradise Lost

Smart female lead shoujo manga

kanoko from warau kanoko sama and koi dano ai dano (the sequel)

You should really read, “ I reincarnated into an prime game as a villainess with only destructive flags”.
It’s really good and worthwhile, it’s on going, you can read it on manga rock ( a great manga app)

Okitegami Kyoko no Biboroku should be the one.

Kisshou Tennyo - a femme fatale story; really interesting as it explores gender roles and the hardship experienced by females

Akatsuki no Yona - starts out a pampered princess but progressively becomes emotionally-strong and uses her femininity to her advantage (she knows she's not physically strong but has other strengths)

Cat Street - finds her own path

Anime/Mangas w/ smart female tacticians:
Song of the Long March
Katanagatari

Cunning female chars:
My Secret Brother
They Say I Was Born a King's Daughter