ACF-conditional-display-for-non-select-fields.js

(function($) {

    acf.add_action('ready', function( $el ){

        //Identify the field you want to check against.
        //Use a class to handle scenarios involving repeater / flexible content where multiple instances exist
        var $field = $('.example input');

        $field.on('change', function (evt) {

            //Comparing against taxonomy field values to determine which other fields to show / hide
            switch($(this).val()) {
                case '27':
                    //A semi-strange "up over down" jQuery to ensure if inside a repeater / flexibl content you show/hide only the desired field
                    $(this).closest(".example").siblings(".conditional-display").removeClass("hidden-by-conditional-logic");
                    break;
                default:
                    //All other states, lets ensure they are hidden    
                    $(this).closest(".example").siblings(".conditional-display").addClass("hidden-by-conditional-logic");
            }

        });

        //On initial page load - ACF data may indicate that a field should be shown instead of hidden
        //Each ensures it craws for all repeaters / flexible content
        $field.each(function( index ) {
            if ($(this).val() == '27') {
                $(this).closest(".example").siblings(".conditional-display").removeClass("hidden-by-conditional-logic");
            }
        });

    });

})(jQuery);

ACF-validation.php

<?php

add_filter('acf/validate_value/name=conditional-display', 'validate_conditional_display_field', 10, 4);

function validate_conditional_display_field($valid, $value, $field, $input) {

        // bail early if value is already invalid
        if (!$valid) {
            return $valid;
        }

        //Loop through each flexible content
        foreach ($_POST['acf']['field_5775b7d7f4f20'] as $k => $data) {
        
            //Compare Taxonomy field and whether the 'conditional-display' field is empty
            if( $data['field_577aa1d7d9713'] == "27" && !$data['field_5798d4fa12790']):
                    $valid = __('You have chosen (taxonomy) so you must provide a (conditional display field name).');
            endif;
            
        }

        return $valid;
    }
    
?>