I’ve been researching using Netlify Functions to control access to all pages on the site using user identity.
This would be free to setup using Auth0.
It doesn’t block the page itself, but you could make your page empty unless the user is authorized and you could implement your own logic perhaps in the function to check the identity of the user and which page’s data they are requesting.
Note that one could spoof the page was is requesting data from, so that is not secure, but you could control the data for that page based on user access. And have a 1:1 mapping of data and pages
Securing Netlify Functions with serverless-jwt and Auth0