There's no way to have SSR'd gated content without paying a gazillion bucks to either netlify or next for role-based redirects.
Even if I would go for CSR'd content for the gated part, I'd have to fiddle with JWT tokens.
To handle users, I'd have to use a 3rd party service such as oauth, since zeit doesn't support users, and netlify's model is severely limited.
For a CMS, I'd have to again go for a subscription model.
Data and APIs are also another issue. There is no way to use something like Strapi since that needs to have a real DB behind it.
Now, to orchestrate the users for role-base redirects, oauth, payment gateaway data and everything else... I've no idea where to even start.
I'm not asking that flippantly. And I know there are plenty of reasons not to use WP, so I apologize if this is a dumb question.
It just seems like WP might solve that particular problem for you without much work. And it solves other problems too, like managing users and tracking revision history for every piece of content.
I think Digital Ocean has a one click setup for WordPress. WP isn't my favorite software to work with as a developer, but I use it when it's the right took for the job because for the most part, I've been able to deploy it and forget about it because it has just kept chugging along and getting the job done without any intervention from me.
Wordpress is a dumpster fire and I hate it with a passion, though. Like, viscerally, almost as much as I dislike Drupal and Joomla. I'd use the term PTSD but that strikes me as insensitive.
But I still use it for many clients, because it's the simplest, easiest solution that other (and crucially, cheap!) developers can take over when I'm not there anymore.