It's 2019 and I'm trying this for the first time. I almost went searching for alternatives but then I got the idea to search these forums.
Turning on legacy mode allows me to use my landscape-mode laptop to connect to my desktop with 2 monitors in portrait mode.
It might help future users if legacy mode was default (though I assume it is legacy for a reason), or there was a rotate button in the GUI, that if nothing else had a popup that said "please reconnect with Legacy mode on in order to correct the rotation."
