Create server available on HTTP/HTTPs that can be used with PM2 - node.js

Question

I'm trying to create a Socket.IO server that has the following goals:
Accessible on the local network of virtual machines using HTTP (http://<server-local-ip>)
That can be accessed via browser by users through the HTTPs protocol, and that can also make the socket.io.js bundle available via HTTPs (https://socket-server.example.com)
That uses all available CPUs in the virtual machine (the server will run in just one virtual machine) - (Possible with PM2)
Have the ability to be automatically restarted in case of failure (Possible with PM2)
For that I created a script based on the Socket.IO help article teaching how to use PM2 and this question that teaches to use HTTP and HTTPs.
/**
* pm2 start basic.js -i 0
*/
const http = require("http");
const https = require("https");
const { Server } = require("socket.io");
const { createAdapter } = require("#socket.io/cluster-adapter");
const { setupWorker } = require("#socket.io/sticky");
const { readFileSync } = require("fs");
const httpServer = http.createServer();
const httpsServer = https.createServer({
key: readFileSync("./localhost-key.pem"),
cert: readFileSync("./localhost.pem")
});
const io = new Server(httpServer, {
cors: {
origin: "*",
methods: ["GET", "POST"]
}
});
io.adapter(createAdapter());
setupWorker(io);
io.on("connection", (socket) => {
console.log(`connect ${socket.id}`);
});
httpsServer.on("request", (req, res) => {
io.engine.handleRequest(req, res);
});
httpsServer.on("upgrade", (req, socket, head) => {
io.engine.handleUpgrade(req, socket, head);
});
httpServer.listen(8080);
httpsServer.listen(4430);
Using HTTP and HTTPs always throws an error.
Via HTTPs I can't load the socket.io.js bundle. But as this service will be available via browser, it will be necessary to make it available via HTTPs to users.
Direct access via HTTPs displays:
{
code: 0,
message: "Transport unknown"
}
This is just using the first part of the script, without trying to run with PM2 yet.
When placing the PM2 part next to the script, other errors appear:
I have to remove the code httpServer.listen(3000); for HTTP to work
When I connect to HTTPs the code never finds the session, so it keeps trying to reconnect endlessly.
socket.io.js via HTTPs remains unreachable
Even using HTTP socket.io.js and connecting with <script src="http://localhost:8080/socket.io/socket.io.js"></script> <script> const socket = io('https://localhost:3001');</script> nothing works
However, if I run all this over HTTP only, without requiring HTTPs, it works perfectly.
What am I doing wrong for HTTP/HTTPs not to work together?
Will I have to make the server available only in HTTP and create a proxy via NGINX to support HTTPs and call the HTTP server?