Yes your webrtc will need to be on its own port, but it doesn’t HAVE to be port 443. So you can keep port 443 as you have it now for HLS and HTTPS, but you’ll need to configure a different port for webrtc.
We have port 443 set as for the default though in Engine for webrtc, so if 443 is in use for something else already, you’ll need to set a different port for webrtc and make some small changes
Please see this post for steps:
Please play close attention to this 
In this example port 444 was used instead for webrtc.
*when you enter your signaling url, you will need to enter it with the port 444 instead of 443.
wss://5ab4321c0xxxx.streamlock.net:444/webrtc-session.json