I'm curious is there any hetero korean manhwa or webtoon that has smut scenes like this ot...

i suggest going to lezhins, go to ranking and then click mature. if you find any you like, you should be able to find them on here. mangago also has a feature where you can select different topics (smut included) and then find stories based on the topics selected

also some suggestions are
-talk to me
-liliths cord
-perfect half (not on mangagao anymore)
-capture (isn’t too bad either)

a fool and a girl
What's going on
Innocent sin
Secret Class(hard core stupid storyline but u just want to read more for some reason)
Sex exercise(interesting premise)

lucia has smut??? why did no one tell meee!
but anyway did u mean just porny comics in general or specifically ones in a historical or fantasy setting? cause if its the latter, tragically, at least in english? im not finding much comics with explicit sex scenes that arent set in modern contemporary world. like there's alot of BL like that, a couple of Yuri that fit that description but as far as het goes its like this one, apparently Lucia?? and....Asura's Bride, which is a very short comic u can read on here or webtoon eng and it has like one long (very prettily drawn and uncensored!) sex scene between the leads. but the X rated version is only available on patreon if u want to get it the proper way. wait, i guess lilith's cord also counts, its def smutty but its not rly historical or high fantasy it feels very like those ecchi animes marketed to young men. basically, i was not moved by it lol, but the art is pretty enough.
It is weird that fantasy and historical romance is such a common/popular genre for romance manhwa, manhua and webtoons yet i rarely ever see smut comics that use such a setting for het couples? its so bizarre. like What is the reason! oh well, if u ever need recs for smutty genre fiction starring queer couples just know that i have a List ready to go lol.