The ACF JS files (API) are only loaded on the admin and will only work for editing. The ACF JS does not run on the front end and cannot be used to get values of fields.
If I am somehow misunderstanding where you are attempting to use this you need to use acf.getField() and this function requires a field key, not field name.
https://www.advancedcustomfields.com/resources/javascript-api/#acf.field
