Same problem here with 201207 .iso. Mine didn’t show the desktop with wayland. So I selected regular plasma. Anyway see my comments in this post:
I have it semi working now, but there are still a few things that are not suppose to happen. After manually install discovery and later discovery-snap, those programs keeps on running in the background after it is closed. That causes a chunk of memory to be used and it delays the shutdown of the machine. After a fresh boot, discover opens unwanted automatically after logging in.