Thanks for the inputs, I did something like what John purposed at first but then I did solve this myself with standard jQuery. I simply added a class to the field, “datepick” and then loaded a jQuery datepicker with this code in the wordpress admin.
jQuery(document).ready(function(){
jQuery( ".datumpick .acf-input input[type=text]" ).datepicker();
});
Its not the ACF datepicker but it is just like it and works just as I want. I can add a date with the datepicker or I can write any word or sentence.
Hope it may help someone in the future as well.
