I'm a fairly new music producer, and one of the inherent problems with it is that it means you have to do all the work yourself: sound design, any vocals, mixing, and mastering. There's quite a few companies that make this easier by providing royalty-free samples. Sometimes it's a free pack being given away, sometimes it's a one-time purchase. Problem is, samples are set in stone, what you download is what you get. This is a problem with vocals, because you can't really add any more words to them, or anything like that.
With that said, there are a growing number of websites that use AI and text-to-speech to create audio files in a pre-chosen voice. Many of these also feature a way to create a new "voice" by providing some sample audio. So one way around this would be to take a bunch of samples with a voice you like, and use them to create a new AI voice; you could then use it to make any samples you want.
My question is, is this legal? My assumption is that if a sample is being offered royalty-free, then the vocalist had to have agreed to a one-time payment. And it's pretty routine to cut up these samples in an arrangement, in addition to manipulating the sound of the voice itself. If the creation of the AI and production of new samples is this same kind of manipulation, it seems like it should be fine. On the other hand, I could see an argument that this is just stealing the voice of the artist. Extra question, if you were mangling the voice so much it didn't even sound like the original anymore, would that change things?