I know what "MVC" _stands_ for, but I'm asking what _context_ you mean that in. Are you talking about how to define your server-side data models and endpoints? How you're organizing client-side fetching and caching?
Normally "MVC" as a concept doesn't get used in the React ecosystem (the way it did with Backbone.js).
FWIW it's certainly _possible_ to use React as a script tag, but it's extremely rare. It's normally expected that the frontend _is_ actually bundled and compiled, whether it be using a pure-SPA build tool like Vite, or one of the full server-side frameworks like Next or Remix.
Note that the SPA build output is just a set of static HTML/JS/CSS files, which do not require a separate Node server process for hosting - they can be served by any HTTP server.
My own advice would be to use Vite and build as an SPA.
_If_ you absolutely want to use React as _just_ a `<script>` tag with no build step, I'd recommend also using https://github.com/developit/htm to at least give you JSX-like syntax for writing your components.