@the_navigator digikey for components - mouser cor conrad if you need to.
You can track a performer very well across a stage with proper lighting and a good IR camera, that will give you lense support and a myriad of other features. Depth cameras are good for a limited number of things on a stage due to their restrictive performance and FOV. Machine vision or even security cameras will do most things you think you need. You dont get skeleton tracking but in reality doing that on stage is so restrictive you may not want to put your performers through it - taking away their autonomy to serve a naff machine.
Everything here is done without depth cameras - as tracking as it gets: