TextArea.value should be TextArea.text
https://develop.kde.org/docs/extend/plasma/widget/configuration/
TextArea
property alias cfg_variableName: variableName.value
Should be
property alias cfg_variableName: variableName.text
https://develop.kde.org/docs/extend/plasma/widget/configuration/
TextArea
property alias cfg_variableName: variableName.value
Should be
property alias cfg_variableName: variableName.text