Running latest Strapi v4 on Plesk Obsidian 18.0.46 with Node 16.17 the server.js code has to be this in my experience:
// server.js content:
const strapi = require('@strapi/strapi');
strapi({
autoReload: true,
serveAdminPanel: true
}).start();
The suggested code in Strapi docs doesn’t work, it seems we have to force autoReload.