While I understand your point, they do deserve to reap the benefits. Because they were unfairly brought the og character's body. They had to clean up the things og character messed up. The rewards they get are worthy for them as well because they actually cleaned up the mess.
Most of the time og characters can't do that, because they're living in the moment that fl's read about. When you are observing, you get remedies quickly. But when you live in it, your mind is more influenced by emotions and make more mess.
So I understand both characters, but the new fl 'reaping' benefits are well worthy of it.
As a hint of a spoiler, this story won’t be like that. You should keep reading to find out what happens
see this is why imo going back in time > transmigration bc i hate seeing the og character not getting justice and closure while the new person inhabiting the body reaps all the benefits