Oh my God, you're right. I've done attached the links I'll do it again, hope these suits your taste :
1. https://www.mangago.me/read-manga/spicy_sugary/
2. https://www.mangago.me/read-manga/gravity_eyes/
3. https://www.mangago.me/read-manga/hachimitsu_darling/
4. https://www.mangago.me/read-manga/sono_kuchibiru_ni_yoru_no_tsuyu/(it's hard rape, if you don't like it, don't read. But i'll say this is give you strange reading experience, because aensei wrapped it well)
5. https://www.mangago.me/read-manga/koh_boku/
6. https://www.mangago.me/read-manga/ochibure_shinshi_ni_ai_no_uta/
7. https://www.mangago.me/read-manga/yasashii_anata/
8. https://www.mangago.me/read-manga/double_fake/(this is not old, but idk i just want to recommend because this is good XD)
Ugh 2 titles overlaps with words, I will attach it again :
-4. https://www.mangago.me/read-manga/sono_kuchibiru_ni_yoru_no_tsuyu/ (it's hard rape, if you don't like it, don't read. But i'll say this is give you strange reading experience, because sensei wrapped it well)
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8. https://www.mangago.me/read-manga/double_fake/ (this is not old, but idk i just want to recommend because this is good XD)
I actually suprised that it is a good story with a lovely couple. Character development usually becomes so weak in old mangas but we could observe changes in their emotional states and one-way thoughts in this manga. I personally love the couple and it is good read