To use the WGT app from Apple's app store, you need a MacBook with an M1 or M2 Pro chip.
What Mac do you have?
Edit
So, I verified the app works with Sonoma (both the OS version and from the app store).
It may be the case that you'll have to run an uninstaller app. I'm guessing you simply moved the old app to trash, emptied the trash, and rebooted.
If that's the case, I'd find a good uninstaller from the app store and use it to see if it can pick up any (potentially) missed files (for example, something buried in Library).