"Download" components should be coded as links and not buttons (assuming the download component does not perform any other actions). For example, if a "download" component functions as a way to save, update, and download form content, a button would be more appropriate. However, if the component solely functions as a way to download or open a static file, then a link should be used.
Would your team benefit from having an accessibility specialist available for regular consultation on questions like this? Explore accessibility consulting services from Accessible Web.