Are you sure the json has the right values? For example, where is the “key” for each group? i see you are using an “id”, but…. shouldn´t be “key” ?
Also the entire json generated must be inside [] and is not.
Also i notice you are using ‘options’ => array(…. but in my exported json from ACF UI, that thing do not exsits, position, hide_on_screen and so on are “alone” not as part of an array.
So, i think the array that is transformed into json is not well formated and that´s why when importing nothing happens.
Did you test with just a small and simple array let´s say a group with just one text field and no complex location rules?
