Guiltythree
Hear me out, what if the second idea is true. Sunny may have learned an unbearable truth(A terrible secret seems to be mentioned concerning the pyramid) inside the nightmare, and in an attempt to save himself from it he was forced to create this item thus sealing himself inside it. That sealed person might very well be inhabiting the sin of solace. Who by all standards is not acting much like it used too, the sealed Sunny knowing Sunny wouldn’t trust it, he’s leading Sunny to conclusions in an “Unhelpful manner” by having Sunny look for things the “Sin of Solace is hiding”. Perhaps any changes that Sunny took on were reverted by traveling through time, or are somehow stored within the item. In retrospect it’s a little outlandish, but it would be so cool!