You can use what you want, but "should" is a strong word. Every action has some consequences. You could use it but keeping in mind that this product is only ispired to the one of the original Author, and you cannot take credit for their work. You could do it with a contract written by the author. In absence of it you should obey the copyright laws, without altering the opera within the time windows covered. You could use it on expired works, like classics, but disclosing what you are doing to the end user

We are attached to the concept of "Who made it" because we reason from a meritocratic perspective. I did most of the work, so I should get the credit. The entire reason because the copyright norms exist is to push innovation. We are asking here if we could use some product to implement a modification on it, making it better, worse or just different. We should be clear that this is what we are doing, but we should be able to innovate using things from the past once the people who made it are gone. Not all Ai use should be permitted but the question underlines the possibility of at least one permitted use, and I think this use should exist if agreed before or enough time passed (and in absence of a direct prohibition from the author). Humans keep taking things from the past and construct on top of it, this is not different.

Your argument is not on point, I kept underling that the process should be clear and accepted by the end user, without information this would be a scam