Should Webpack be used for React app rendered via SSR on Express?

Currently working on a website where I'm using a React front-end and Express backend. Looked into CSR and SSR rendering of the web page and was considering doing SSR.

For CSR I understand that webpack helps to split and minimize the code that users receive in the initial load. But for SSR rendering (i.e. Express return each page via an endpoint), is webpack still necessary (as users don't get as large of an initial load)?

(If webpack is crucial/important for SSR, is there a good tutorial somewhere for it?)

(Perhaps a separate question but with SSR I'm assuming Express endpoints replace React Router setup)