I created a custom post type named “survey” that contain a text object formatted as JSON. It’s group name is “Survey Result and its field name is “survey_result”.
As you can see in the image link below, I can easily create a new survey and save the survey result in the post_content_field, but I have yet to learn how to save it in the acf_field. The “survey_result” field shows up as “null”.
My mistake was having the wrong path for my register_rest_route(