Always happy
https://www.mangago.zone/read-manga/katekyo/
https://www.mangago.zone/read-manga/honto_yajuu/
https://www.mangago.zone/read-manga/sasaki_to_miyano/
https://www.mangago.zone/read-manga/heart_no_kakurega/ ( main couple happy happy, second couple drama happy)
https://www.mangago.zone/read-manga/karasugaoka_don_t_be_shy/
https://www.mangago.zone/read-manga/kimagure_goshujin_to_oshikake_neko/
https://www.mangago.zone/read-manga/ring/
https://www.mangago.zone/read-manga/link_and_ring/
https://www.mangago.zone/read-manga/family_now_and_forever/
Darama happy
https://www.mangago.zone/read-manga/oko_sama_star/
https://www.mangago.zone/read-manga/kowagaranai_de_soba_ni_ite/
https://www.mangago.zone/read-manga/kami_sama_no_ekohiiki/
https://www.mangago.zone/read-manga/super_natural/
https://www.mangago.zone/read-manga/boku_no_papa_to_papa_no_hanashi/
https://www.mangago.zone/read-manga/until_i_meet_my_husband/ ( based on a real couple * the author and his husband)
https://www.mangago.zone/read-manga/life_senjou_no_bokura/
And I guess that's all I can think of
All happy endings
I just watched Good Omens, and I would really love stories with a happy ending rn