Set Environment Value to .desktop File
You can add an environment variable to an application by editing its
.desktop file. For example, to run “digiKam” with the environment variable
APPMENU_DISPLAY_BOTH=1, find the corresponding digikam.desktop file and
add the setting of the variable, via the env command, to the entry “Exec”
source: https://askubuntu.com/a/144971