The one negative side-effect of sidenav is that in responsive view on mobile, it collapses to a navigation menu. So we can't use this anyway. I mean, it does make sense as it is called sidenav, for navigation.
So we still need an option for a left sidebar that isn't a navigation sidebar. There is a template modification to add a left sidebar, but I would have to wrap it in a conditional to appear only for this page node. I may have to resort to that.