@malevolentbutticklish First, by purchasing a copyrighted work, in whatever medium, you are purchasing a copy of the work only. Copyright law, in the US, is regulated by Title 17 of the United States Code, which is also consistent with the Berne Convention regarding international rights.
_(Edit)_By the way, I am not a lawyer, I am only sharing information that I have collected over the years in dealing with mprotection fo my own intellectual property
US Code Title 17 § 202 delineates the difference between ownership of material object (in our discussion, a digital recording) and the rights to the intellectual property contained within that material object.
Quote (with my added emphasis):
Ӥ 202. Ownership of copyright as distinct from ownership of material object
Ownership of a copyright, or of any of the exclusive rights under a copyright, is distinct from ownership of any material object in which the work is embodied. Transfer of ownership of any material object, including the copy or phonorecord in which the work is first fixed, does not of itself convey any rights in the copyrighted work embodied in the object…”
(Edit) BTW, I am not a lawyer, I am just sharing what I have learned over the last forty years trying to protect my own intellectual property