OK, I see that port 8080 is a duplicate of port 80 and that port 8081 shows the Hubitat Diagnostic Tool but what is the purpose of having ports 443 (normally https) and 8443 open when they only return a few bytes of ???

80 and 8080 are http web interface. 443 and 8443 are https web interface. 8081 is diagnostic tool. Pretty standard stuff. They are safe inside your local LAN and not meant to be forwarded externally. If you cannot trust the people on your LAN then enable hub security.