Just answering my own question: Following some more digging we can just use vector.im or matrix.org. In fact browsing to my Element web app on mobile suggests I configure the native mobile app using vector.im.
However, when I do, I get errors suggesting something ain't right. I set the well known and even opened 8448 in my fw. Any help @girish or @nebulon can give to help a poor, tired sysadmin out? 😉 please
oh, yeah ... and Happy New Year! 🎉