So, I looked at the NGINX Plus implementation and I’m not looking to pay for their service at this point.
I also tried to hack it together by adding a folder under pages called ‘account’. I then put the markdown files under that directory and tried to protect anything under the account/* route. It’s sort of working in that auth0 still tries to authenticate me when I browse to ‘/account’ and I’m able to build the markdown page via the gatsby-node.js process and I’ve confirmed that with graphiql. So, the page based on markdown was built and the path is src/account/subdirectory/markdownpage. It appears to work with that workflow, however, if I just copy the url for that full path, open a new browser, paste the URL and browse to it, it doesn’t enforce the authentication and just shows the page. If I cut off the markdownpage part of the URL and browse to /account/subdirectory it does initiate the auth0 pop-up. So close, yet so far.