@kris What you're trying to do might actually be possible using a catch-all along with a normal dynamic route. According to the Next.js docs, a normal dynamic route will take precedence over a catch-all route.
That means that you should be able to have your /pages/[uid].js route for your /about and /contact-us pages.
Then you could also use a catch-all route such as /pages/[...uid].js for anything with a folder such as /news/new-website.
Give that a try and let us know if it works 