Flux app open but inaccessible on my MacBook Air

I use Flux. Although mac says it is open I can’t access it even when I click the icon. I can’t uninstall it either because I can’t access it and it isn’t appearing on force quit. When I try to use trash to delete it a note comes up saying I can’t delete it while it is running. Tried to install a new version but get the same message - that I can’t install the new version while the old one is running.

[Re-Titled by Moderator]