I'd highly encourage you to look into shiny more. No, it's not django, but it's a much richer framework than dash, and you can always bring your own HTML if what it generates for you isn't sufficient.
But the fact that there's no Django for R means shiny's a dead-end for a production web app.
ambiorix might be what you're looking for.
check it out: https://ambiorix.dev/
it provides: - routing - api generation - templating - web sockets