I don't know whether you will like this but these are some pretty good ones with green flags
https://www.mangago.me/read-manga/omae_no_tame_ni_houritsu_kaetakara_ore_to_kekkon_shitekure/
https://www.mangago.me/read-manga/autobahn_romance/
https://www.mangago.me/read-manga/nagahama_to_be_or_not_to_be/
https://www.mangago.me/read-manga/love_at_first_fright/
https://www.mangago.me/read-manga/tiger_and_tiger_gourd
https://www.mangago.me/read-manga/bongchon_bride/
https://www.mangago.me/read-manga/kimi_no_yoru_ni_fureru/
https://www.mangago.me/read-manga/gentle_forest/
https://www.mangago.me/read-manga/exclusive_no_love_zone/
https://www.mangago.me/read-manga/marry_you_yes_i_will/
Just in case you are yet to read this tittle, I will recommend...
https://www.mangago.me/read-manga/kouguu_no_omega/
I think this one have the same vibe. The calm and sweet king, and pretty reckless lover. The story pretty sweet here.

Umm can anyone reccomend more manhwa like thiss...!!!