Italian citizenship

Good afternoon,

I have a hugeeeee question regarding Italian citizenship.

My aunt was born in 1979 (expat parents) in Frosinone and after her birth, she and her family moved back to Latin America.

Nonetheless, she's very keen on trying to get Italian citizenship - or at least find a way to make it easier for her to move to Italy again.

According to what I've read, you are entitled to it wether you've been living from birth and right before your 18th bday you have to make a decision wether you want to pick the Italian passport (wouldn't apply to her)
Or , if your parents nationality and the state where you were born allows it?? Something like that.

Could anyone point me out on a way to figure out this loop?
Or a way to perhaps live in Italy and apply for the citizenship after a while that is made easier due to the fact she was born and our family lived there, etc..

Additionally, It is worth pointing out we have an Italian grandfather who never recognized his kids (only one) and this has been the cause of all issues in my family.

Thanks for the help!