Hello, don't worry, accordong to your situstion, it's easy to fix.
(1)Quit the app with the Apple Menu. Apple Menu > Force Quit.
(2)Quit the app with Activity Monitor. Finder > Applications > Utilities > Activity Monitor, search for your wanted app then double-click it, then click Quit.
(3)Uninstall app with effective software like iBoysoft MagicMenu. It allows you to uninstall an app with a few clicks, even for the app and the leftovers together.
- Free download, install, and open it.
- Click Extension in the left menu, then find Uninstall App and click the download arrow.
- Finder > Applications > Right-click your unwanted app and choose Uninstall > Uninstall > Yes.
So easy to delete the app, hope you can succeed in the end.
Also read: The Item Can't Be Moved to Tarsh Because It's Open.