No, it is not ethical; the same way it would not be ethical to steal the writing of Shakespeare and claim it as your own. Shakespeare is known for his writing style and vocabulary. If you see a part of his plays, you will most likely be able to distinguish it from a modern piece of writing, and you need to ask yourself: is it plagiarism to blatantly copy the work of a famous writer and steal what they are known for and present it as your own? I do not think so, and in the case of a singer or any artist who creates their art through the use of vocals, recreating it through AI is the same as copying the work of an artist who creates their art through words and writing, which is commonly referred to as unethical and can lead to academic and legal penalties. So, in which case would it differ from plagiarising the work of an artist who creates art through the use of vocals? That is why using artificial intelligence to recreate the voices of dead artists' should not be deemed ethical. Thank you