delete an icon from menu bar; ⌘ - drag does not work

This concerns the Deepl translator desktop app. I cannot contact them unless I become a paying subscriber and I do not want to do that, so I am hoping someone here can advise me.

I tried the Deepl translator desktop app. I don't want it any more. When I quit it, and try to delete it from the App Folder, I get an alert saying it is open and can't be deleted. I thought maybe it had something to do with the menu bar icon it placed at the top of the screen so I tried to delete that by ⌘- dragging it off. But the no-can-do circle with the diagonal bar appears on it and it snaps back to the bar.

Any idea how I can delete the app and/or get rid of the menu bar icon.

late 2015 iMac running 10.13.6.