You would need to build custom JavaScript https://www.advancedcustomfields.com/resources/adding-custom-javascript-fields/ and use the ACF JS API https://www.advancedcustomfields.com/resources/javascript-api/
You would need to add actions to detect changes in the fields you are interested in. You’d also have to modify the datepicker using https://www.advancedcustomfields.com/resources/javascript-api/#actions-date_picker_init. And you’d need to interact directly with the jQuery date picker https://jqueryui.com/datepicker/
Sorry I can’t give you much help as far as coding goes. The only example I know of of working with the date picker is here https://support.advancedcustomfields.com/forums/topic/autocomplete-end-date-when-start-date-is-selected-in-jquery-date-picker/ and that is old. There are no examples of doing this with the new ACF JS API.
