In many respects 11 labs is currently the best in class for artificial voices. In terms of automated performance of an entire screenplay there's really nothing out there that's going to give you something usable for a final product, But you can use eleven labs voice to speech (not text to speech), Perform the roles yourself one line at a time, And get a pretty believable and usable full cast performance out of one performer. It's $20 a month or so, And you'd be looking at a considerable amount of work to get a solid performance. Right now that's pretty much the route to the best possible result if you wanted a believable screenplay read.