[flimsypremise]

What's rendering the pages on the server? Because if its not javascript, and you still have a frontend build, you have a repository with two separate builds, and builds are expensive to maintain. If your containerizing, you need two different containers, each with a dependency management system, a runtime, probably a separate workflow for development and production.

There are many ways to render pages on the server using a single JS builds, most template rendering engines have a node implementation, and most javascript frontend frameworks have a mechanism to render components statically to a string. If we're talking about a simple, mostly-static website, the content is going to be cached so the performance of the backend isn't a huge factor. So just use JS for the whole thing, and save yourself a build.