404 error in production, working fine in dev (Nuxt 3)

First let me say that I’ve checked out several other issues already, but none of the following solutions posted over there works. Some of this things I tried / made sure:

• @nuxt/sitemap is in dependencies
• Changed export default defineNuxtConfig( { ... } ) to module.exports = { ... } in nuxt.config.ts

As stated in the title, /sitemap.xml is working perfectly fine in dev mode (npm run dev). However, when building the site (npm run build) and starting it (nuxi preview), the site returns my 404 page. The /sitemap_style.xsl file is available in production mode. It happens both on my local device as well as on my production server (NGINX reverse proxy). My thoughts are that this is a bug with Nuxt 3, but I cannot say this with 100% certainty.

This is my nuxt.config.ts sitemap object:

sitemap: {
    xslUrl: '/sitemap_style.xsl',
    routes: async () => {
        const { data } = await axios.get('https://api.example.com') // this is the actual URL in my code, which is working
        let routes = []
        data.data.forEach((page) => {
            let route = { url: page.slug, lastmod: page.date_updated }

            routes.push(route)
        })
        return routes
    }
}