I have a landing file which is in pure HTML. (landing.html) I want the main URL of the website to be this file and the rest of the URLs to go in the React app.

For example:

example.com -> landing.html
example.com/app -> react app 
example.com/login -> react app

As I said, I want the main URL to read the landing.html. But the rest of the app should read the build version of React.

If it's possible i want it to be a part of the React app and not adding it directly in build folder. After running build it should be automaticly in build folder so basicly kinda implicitly to be a part of react app.

One more thing I dont want to convert it to jsx.