Hello!! I’m looking for manga, manhwa, or manhua with yandere guy (preferably the main character, but its good too if the yandere guys is second lead). Please no yaoi🙏 Thank you so much ❤️

Kubera - Takes awhile.
Charlotte has five disciples - Maybe? Early to tell, but has possessive/obsessive characters.
Abide in the wind
Raise wa tanin ga ii
Metronome - Either dropped or slow updating
This Time I Will Definitely Be Happy!
The hero suddenly proposed to me, but... - Indefinite hiatus
Pale Horse - Dropped due to official English release

Maybe not yandere, but possessive/obsessive
The reason why Raeliana ended up at the Duke's mansion
Lan Chi - Dropped due to official English release

Thankss but most of the im currently reading but still thank u so much for your recommendations

Have you tried the any of the old series? If I remember correctly:

Hana Yori Dango (main guy)
Hot Blooded Woman (the supporting guy but not obvious at first)
Meru Puri (or was it Vampire Knight—this is a mess btw)
Please Save My Earth (for a reason! Unfolds slowly though)
Kare Kano (never finished this though)
Sonan Jyanaiyo / Sonan Jee Nayo
Gokusen (does Shin count as yandere?)

On second thought, most aren’t nice at first and becomes nice later on so technically only Hot Blooded Woman and Kare Kano would count as nice/gentlemanly at first then obsessive/possessive later.

Sorry i just saw your comment. But anyway, thankssssssssssssss ill read those mangas you recommend

aishite kudasai, sensei

Risou no Kareshi-tachi

Hakuji

Paperweight eye

100% perfect girl he is a complete gandered even locking her up at one point. This other interest is a huge one too