How do VUE projects that don’t use webpack do server-side rendering?

I have a project that doesn’t use WebPack, which was developed by Vue referenced by direct CDN, and now I’m going to do SEO. Let’s change this SSR, please give your honorable bosses some advice.
I used vue2.

You can use Nuxt, a framework developed based on Vue, specifically to solve the SEO problem caused by single-page applications such as Vue.

The version of NuxT2 I used before feels relatively simple to get started. If you use vue, migrating code to nuxt should not be too troublesome, and you just need to learn one more framework.