I can’t see the whole plant and I could be wrong, but you could have a variegated Monstera on your hands.
https://thursd.com/articles/monstera-deliciosa-albo-variegata-the-most-expensive-plants-in-the-world
My own Monstera is doing well, and I don’t water it too often. Usually once a week and limited. But I have the feeling that all plants are a little different. It could also lack nourishment.
Am I the only one who thinks there haven’t been big 'mistakes" in their life, just, you know, life? I mean, sure, there are things I would do differently given the chance, but not something I would call big mistakes. I would definitely go for the money - I would even pay money not to have to go though my teens again lol