Also, the thing with using classic stuff is that you really don't want to use a theme past the Twentyseventeen theme, but definitely not past the Twentytwenty-one theme. This is because these themes become more and more dependent on the block and site editors, up to the point where they don't have much design out-of-box because they assume you're going to use block patterns and such to design your site. So if I were to use the latest default theme with classic stuff things would be incredibly bare on this site without an easy way for the site owner to change it.