WordPress has its own rest API you can use WordPress API and a frontend framework like Vuejs or React to interact with WordPress, actually, WordPress is your backend, and the frontend framework is your frontend look at the example below:
https://52hertzcouture.com/
check out link below:
https://github.com/WP-API/node-wpapi
i think using wordpress as backend and a frontend framework like vuejs as frontend is a good idea if you want to use wordpress and extend your website.
https://52hertzcouture.com/
https://backend.52hertzcouture.com/wp-login.php
about nodejs there are some packages like node-wpapi that can help you to connect to wordpress rest api with nodejs as a client and do everything a client can do, for example make posts, make pages, etc.
check out link below:
https://github.com/WP-API/node-wpapi
i think using wordpress as backend and a frontend framework like vuejs as frontend is a good idea if you want to use wordpress and extend your website.