Opening a new terminal should work, since those commands you posted affect just the running shell. If not, you broke something else.
Edit: Assuming you pit that export line into ~/.bashrc, just remove it. You might need to enable showing hidden files in your file explorer, them edit it as a text file.
There is no single standard DE on Linux. KDE and Gnome are the biggest ones, and most distros ship with flavors for either. So is KDE non-standard if I install it on regular Ubuntu (which ships with Gnome)? And besides, as the commenter above said, wlroots is one of the few big participants in deciding the wayland protocols, so they are most certainly standard, as standard as any wayland compositor.