Top bar vanishing on non-main monitors

[BluishHumility]

@DisruptionSystemsINC

i cannot for the life of me find a post Having the same issue as me/a valid fix to my issue

Take a look and see if this is a valid fix:

The top panel of the application window disappears when deployed to full screen

Try opening ~/.config/kwinrc and go to section [Windows]. Set BorderlessMaximizedWindows=false, logout and login.