apache - How to set Caddy as a reverse proxy for apache

Question

Caddy 2 is a powerful, open source web server with automatic HTTPS written in Go. I have a web app where users can point their custom domains. So caddy can easily generate ssl with tls on demand. https://caddyserver.com/docs/automatic-https

So I want to set caddy as a reverse-proxy for apache, so I edited my ports.conf file and set it to

Listen 8080

<IfModule ssl_module>
    Listen 8443
</IfModule>

<IfModule mod_gnutls.c>
    Listen 8443
</IfModule>

And my caddy file is set to:

mydomain:80 {
 reverse_proxy localhost:8080
}
mydomain:443{
reverse_proxy localhost:8443

However http works fine with it, but https doesn't work at all. I even tried checking if the port 8443 is free even, changed it to 44301. But it doesnt work.

My questions:

1) How to properly configure caddy as reverse proxy for apache?

2) Should I also change the ports from VirtualHost file? (Tried changing to 8080, but apache wont start)

3) Is there anything I am missing setting it up as a reverse proxy with apache?

Appreciate your help!!