I know I can open a port on router (not recommended)

This is basically the only option you have if you want to provide access from external to selfhosted applications. Just forward the desired ports to the machine where the services are running on.

The less entry points you have, the better. You could “bundle” all web-based applications on port 443 and use a reverse proxy to route the traffic to the actual port based on the hostname the access was done on.

So in your router you define that all https traffic (port 443) is forwarded to your server, and on your server there is running a reverse proxy listening on port 443. All of your applications are listening on different ports that are not accessible from external. The reverse proxy then takes the hostname used for access and proxies the traffic to the actual host based on that hostname.

With this you have only one port open on your router and this one port is only forwarded to one single machine. Everything else is handled by that machine.