Shortcodes do not work in ACF field settings. To do this you should use an acf/load_field filter https://www.advancedcustomfields.com/resources/acfload_field/ and set the default value of the field dynamically in PHP. Or you can use an acf/load_value filter https://www.advancedcustomfields.com/resources/acfload_value/ and if the field has not value then set the value to what you want to be inserted as a default.
