There’s a lot of researchers that demystified it. What they did during that time was combine corsets with puffy dresses to create the illusion of a extremely tiny waist.
Of course they were a little tight but, not to the point of breaking ribs or rearranging organs. The ones you mentioned were used by a small portion of the population, normally of the elite but even amount them, not every woman opted for it.
I will second that saying that most "proof" we have that they rearranged organs are Victorian drawn pictures and diagrams. Which, I will say, you wouldn't want a Victorian doctor within 50 feet of you, so why do you trust that they got the corset right? A traditionally female item in a patriarchal society? Designed, made, and mostly sold by women? Old photographs were also edited to make waistlines smaller, among other things. I don't think it's right to say that corsets are bad if your evidence consists of rumours. I will also say that almost all women wore corsets, even the ones working on farms and in manual labor, so wouldn't people be fainting left and right? But they didn't. Honestly, corsets are not that bad. You just need to have them fitted and you can wear them loose!
Even considering some nobles using tight corsets, people knew it was bad. As well as, you know, it's really hard to pull a corset so tight that it would affect your organs. Maybe squeeze your stomach or something, but not do anything detrimental of you wore it for a short time. Considering women also wouldn't wear these tight corsets all the time, injury wouldn't be common. Even the nobles and royals knew this. It also wouldn't hurt that much, corsets, because women are trained from a young age to get used to wearing one, like young children wearing sports bras(I do believe they did have more comfortable versions used for training) and the ones that seem uncomfortable today only survived because they weren't worn often. Which means, it wasn't common to wear super tight or restrictive corsets and even less popular to not have it fitted. Within the context of the princess, visiting or walking around the palace and not in an extremely formal occasion, her wearing a tight corset would not happen. (This does have exceptions, maybe if she was super obsessed with her body she may wear super tight corsets all the time or her family was forcing her to. Either way, it's not common even among the nobility.
I ain't reading allat. And also from what I've researched, prolonged usage of victorian corsets amongst women still causes some issues especially with young girls. Which is practically the case being mentioned in the manhwa. Point is, those kind of corsets still did exist at some point in history and it's being used in this "fictional" manhwa. End of discussion.
Ch1.
Corsets are not actually....that bad......even working women wore them and..... I'm not even going to try anymore ;-;