I'll never understand how a Crown Prince can ever annul an engagement with a ducal house or high aristocracy in otomege novels with no repercussions. Unless its a super misogynistic society or the family is a ducal house in name only, its basically political suicide to the point of starting a civil war.
No matter what evidence they have against a ducal house, unless its completely powerless, its basically impossible to anything to them. I mean, as a Dukedom, it should have enough land and military might to prevent royalty from risking a war.
Anyways, as for the story itself, expect lost of cooking. Because, if you know Japan, they god damn love their cooking manga. Nearly 90% of isekai, no matter who the plot is, turns into a cooking manga. The only difference is that this one admits it straight off the bat, so you can expect chapters dedicated to cooking.