It seems that next-sitemap is unable to produce sitemaps for dynamic paths, so we're switching back to dynamic server-side sitemap generation

next-sitemap.config.js

@@ -0,0 +1,12 @@
+/* eslint-disable @typescript-eslint/no-var-requires */
+const groups = require('./src/shared/data/groups.json')
+
+/** @type {import('next-sitemap').IConfig} */
+module.exports = {
+  siteUrl: 'https://kspsuti.ru',
+  generateRobotsTxt: false,
+  generateIndexSitemap: false,
+  changefreq: 'weekly',
+  exclude: ['/'],
+  additionalPaths: async () => Object.keys(groups).map(groupName => `/${groupName}`)
+}