I think it's because of the mission. As the mission is a success & there's no side mission or other things, she might as well get transmigrated to another dimension again and again. It's only because of the food that MC still want to walk in one dimension. Perhaps it's also because of the danger that occured to the body she used at the moment
Well it's sas that she can't have a happy ending on her missions and she isn't that free
Poor MC ╥﹏╥ hope she would get a real freedom someday in some other dimension
Tbh i think the first time she transmigate she liked the brother and in the second time she also liked the host but i think our mc doesn't want or isn't allowed to loved that's why she always dies in the end of the story