I think because she was meant to be the head and each time she was deprived by her own family or some other reasons and his dad doesn't do the same regression because he obtained being the head rightfully? Just a theory tho because it seems like it. Time won't stop for her until she becomes what she's destined to be, that kind of thing
Maybe it's part of her power. Spring it's the first season so it can represents beginnings. I don't think everyone in her family can have this power. Remember the boy she save? The boy's family have the power to see if someone is lying but when the boy's tears became jewels, his aunt was shocked. I guess in each of the 4 families, there's a power that only 1 person each century or something can have. Her power is probably to go back in time. The cycle will probably stop when she doesn't feel any regrets after dying. I don't really know of why the autumn's family head remember her in her previous life. Using my theory, he's probably the one person in a century that have an additionnal power.

Isn't this her eighth life? Repeating the same shit over and over again along with dealing with the same shit bags would ruin anyone's mental health to the point you'd probably feel numb to it all. Any reason why she's even stuck in this loop tho? The novel hasn't revealed much either so idk why she's stuck in this bullshit.