There is a long thread about making fields reasonly here https://support.advancedcustomfields.com/forums/topic/read-only-field-2/
and a lot more information can be found by doing a search https://www.google.com/search?q=acf+make+field+readonly&ie=utf-8&oe=utf-8
You would simply need to add code to any filter that you create to detect if the field is being loading in the admin or on the front end of the site.
