Not sure if this is by design with plasma 6, but regardless of changing the display name/logo of an app via KDE Menu Editor, the popup notifications of the app always shows its original name and logo, e.g Discord.
Actually the custom logo shows up properly, but the app name stays the same, it seems like it shows the process name rather than the set app name.
Still occurring in 6.16, an example would be using Vesktop and using KDE Menu Editor to change the name to Discord, the notification would show "vesktop" still.
Created attachment 182997 [details] KDE Menu Editor showing vesktop app name and notification showing process name