Waydroid (Vanilla OS) on Zorin 17.2 Pro doesn't open after install like

Take a look a this thread:

It's possible you just need to change the display server from Xorg to Wayland, as Waydroid won't work on Xorg. In that thread I show a work around this, though.

You're probably already running Wayland, however, since that's the default. It doesn't hurt to check: log out of your account and click on the wheel icon on the lower right:

Zorin desktop means you're using Wayland. Otherwise, you're using Xorg. Feel free to change without fear of breaking anything. If something doesn't work in one, try the other.