Filter by year (custom dropdown)

Good day, please could you assist in creating a year dropdown filter? The datepicker isn’t ideal, as we only want to be able to search within a year, and the datepicker requires selection of a month and day as well.

Please note, the server only allows SFTP and requires a port: 57887

I am working on getting the VPN disabled so that you can gain wp-admin access if need be.

I have tried to implement code as per the documentation – though it’s quite difficult to understand, because half of it is commented out, and not even sure if adding a dropdown (select>options) is even possible?
Here is the documentation I tried to follow. I will post my code attempt below. https://knowledgebase.ajaxsearchpro.com/frontend-filters/frontend-filters-api#date-type-custom-field-filter

Otherwise, I know that jquery UI allows you to change the datepicker to a year using: https://api.jqueryui.com/datepicker/#option-changeYear
As well as providing a range using: https://api.jqueryui.com/datepicker/#option-yearRange
In this case we would need to override the initialisation of the datepicker as it’s created.

// --------------------------------
// Date filter example https://knowledgebase.ajaxsearchpro.com/frontend-filters/frontend-filters-api#date-type-custom-field-filter
// --------------------------------
add_action('asp_pre_parse_filters', 'asp_add_my_own_filters', 10, 2);
function asp_add_my_own_filters($search_id, $options) {
    if ( $search_id == 1 ) {
        $filter = wd_asp()->front_filters->create(
            'custom_field',
            'Date Picker',
            'dropdown',
            array(
                'field' => '_date',
                'placeholder' => 'all',
                // The display date format
                'date_format' => 'yy',
            )
        );
        //add years from 2019 to the current year
        $datesArray = array();
        for ($i = 2019; $i <= date('Y'); $i++) {
            //add all
            if($i == 2019) {
                $datesArray[] = array(
                    'label' => 'All',
                    'value' => '',
                    'selected' => true
                );
            }
            $datesArray[] = array(
                'label' => $i,
                'value' => $i
            );
        }
        $filter->add(
            $datesArray
        );
        $filter->selectByOptions($options);
        wd_asp()->front_filters->add($filter);
    }
}