No. Not yet. I have it as default.
But I think changing Blast ports doesn't have anything to do with it because I can't even access to horizon login prompt with port 4443 that I changed.
I don't think you will be able to change that port for authentication. Not in a supported way I think.
Are you using NAT to forward incoming connections to the UAG? If so, you could do <externalIP:4443> <NAT-TO> <UAGIP:443>.
I appreciate Jay for researching this topic on behalf of me.
Also, thanks for your thoughtful comments, guys.
I even tried manipulating the basic listening port with reinstalling an UAG with an option like the following screenshot, which ended up with no luck.
I will conclude that this is not possible without any additional layer like NAT as Mickey mentioned.