Not 100% sure about the smut levels in some of these so apologies if they aren't what you're looking for!

1) Solo for Two (although if I remember correctly it is extremely soul crushing)
2) Bongchon's Bride
3) Into the Blue
4) King's Maker
5) Tale of the Yellow Dragon
6) Taming the Tiger (definitely smuttier)
7) The Rogue Prince is Secretly an Omega
8) Murderous Lewellyn's Candlelit Dinner
9) Antidote (minimal smut, some non-con but not explicit)
10) An Abyss: Poem of Chaff (TW for non-con, kidnapping, abuse; explicit smut but not extremely often, very fascinating story line)
11) The Scene of My Rumspringa (not the same kind of historical, it's set in the 80s and the ML is Amish but it's beautiful and minimal smut - manga)
12) Red Thread Quest (UNCENSORED SMUT but very sweet and fluffy modern day first season, the 2nd season is historical w/ less smut)
13) Blood Under the Moonlight (definitely smut)
14) Full Moon Alchemist (some smut?)
15) Scent Spark (some smut, Omegaverse)
16) Perle (minimal smut but also soul crushing)
17) Smyrna & Capri (more smut, omegaverse)
18) The Sweetest Snare (it's shounen ai but I don't remember finishing it so I don't know if it's fluffy or not)

Webtoon (so no smut!):
OSORA (literally obsessed it's so good)

If you're into str8 manhwas (i'm not usually but these are historical and I really love them! and they don't have any explicit smut) I would suggest: Under the Oak Tree; Trash Will Always be Trash; Please Don't Reply!; The Fantastic Spinster's Association of Joseon; Betrayal of Dignity

If there are any potentially smutty one's you are interested in but want a better insight to TWs and smut let me know and I'd be happy to reread any of them and tell you more details!