This is fiction tho? How can something like this manhwa, which was made by a korean person who obviously don't know about baroque/rococo/victorian/regenency but only took an inspiration from it and not the entirity of it. This isn't even historical fiction. In the get go, you know this doesn't strive for realism, you could have seen in just the first arc of how much she gains knowledge through dreams, that right there is unrealistic enough
Even the heirarchical dynamics isn't even followed through nor her being a prisoner of war is put into a noble position. The pantsuit that she's wearing is also unrealistic if we follow your thought process, like a lot of things in this manhwa doesn't strive to an accurate depiction of some past western civilization but used as one of the plotpoints to get the story going... So why are you even surprised with how unrealistic this is? This isn't reign where they botched the Queen Mary of Scots through and through
that fact they know what s*x is very unrealistic back then ladies didnt even know how babies where made untill they where engaged and to be wed some even found out on there wedding night