To me, the answer to that is not as simple. I believe those claiming to be divine-kin have a high burden of responsibility to provide an explanation as to why they believe it, one above and beyond just saying this is what they believe.
I don’t expect for people making these claims to prove it with power but they should at the very least be able to show me that they have knowledge above and beyond the average mortal, especially in matters of spirituality and the nature of reality and the multiverse.
As for different mythologies, please do understand that this world already names 2500 different divinities across all cultures (there is a book out there with a big list tho I forget its name) and this is discluding demigods or divine servants of aforementioned deities. No one belief system has a “right answer”, or holds a monopoly in divine grace. To simplify, all of these divinities are valid, if people believe in that divinity.
I myself do not claim to be divine-kin, primarily because I believe divinity to be self-evident. I believe (with some rare exceptions) that if a divinity has to tell others they are, then they have discredited themselves significantly in the act. If one is divine it will be revealed in what they do.
It is kind of disappointing to me that it seems these days those who would call themselves divine, go forth with all their titles first like they are Daenarys Targaryen, and lack works to back it up. After that, the various mythologies aren’t much of a factor. By the perspective of the divine, most of the cultural struggles that mortals have here, are largely irrelevant. All of you mortals are returning to spirit in the end. Your experience in the afterlife is only partially influenced by what you do now. You can go to Heaven, but that’s not the only place you can go. You will be able to see the multiverse as it is.
You will also find that the divine that hold so much regard of the people today also came from less divine roots, and what they DID got them to where they are now. And not all of those things were good, but they got there.
Please let me know if this answers your question.