Converting Date Format in Wordpress Learndash LMS

public function create_section_field( $field_args = array() ) {
    global $wp_locale;

    /** This filter is documented in includes/settings/settings-fields/class-ld-settings-fields-checkbox-switch.php */
    $field_args = apply_filters( 'learndash_settings_field', $field_args );

    /** This filter is documented in includes/settings/settings-fields/class-ld-settings-fields-checkbox-switch.php */
    $html       = apply_filters( 'learndash_settings_field_html_before', '', $field_args );

    $date_value = '';

    if ( isset( $field_args['value'] ) ) {

        if ( ! empty( $field_args['value'] ) ) {
            if ( ! is_numeric( $field_args['value'] ) ) {
                $date_value = learndash_get_timestamp_from_date_string( $date_value );
            } else {
                // If we have a timestamp we assume it is GMT. So we need to convert it to local.
                $value_ymd  = get_date_from_gmt( date( 'Y-m-d H:i:s', $field_args['value'] ), 'Y-m-d H:i:s' );
                $date_value = strtotime( $value_ymd );
            }
        }
    }

    if ( ! empty( $date_value ) ) {
        $value_jj = gmdate( 'd', $date_value );
        $value_mm = gmdate( 'm', $date_value );
        $value_aa = gmdate( 'Y', $date_value );
        $value_hh = gmdate( 'H', $date_value );
        $value_mn = gmdate( 'i', $date_value );
    } else {
        $value_jj = '';
        $value_mm = '';
        $value_aa = '';
        $value_hh = '';
        $value_mn = '';
    }

    $field_name  = $this->get_field_attribute_name( $field_args, false );
    $field_class = $this->get_field_attribute_class( $field_args, false );
    $field_id    = $this->get_field_attribute_id( $field_args, false );

    $month_field = '<span class="screen-reader-text">' . esc_html__( 'Month', 'learndash' ) . '</span><select class="ld_date_mm ' . $field_class . '" name="' . $field_name . '[mm]" ><option value="">' . esc_html__( 'MM', 'learndash' ) . '</option>';
    for ( $i = 1; $i < 13; $i = $i + 1 ) {
        $monthnum     = zeroise( $i, 2 );
        $monthtext    = $wp_locale->get_month_abbrev( $wp_locale->get_month( $i ) );

        $month_field .= "\t\t\t" . '<option value="' . $monthnum . '" data-text="' . $monthtext . '" ' . selected( $monthnum, $value_mm, false ) . '>';
        $month_field .= sprintf( esc_html_x( '%1$s-%2$s', 'placeholder: month number, month text', 'learndash' ), $monthnum , $monthtext ) . "</option>\n";
    }
    $month_field .= '</select>';
    $day_field    = '<span class="screen-reader-text">' . esc_html__( 'Day', 'learndash' ) . '</span><input type="number" placeholder="روز" min="1" max="31" class="ld_date_jj ' . $field_class . '" name="' . $field_name . '[jj]" value="' . $value_jj . '" size="2" maxlength="2" autocomplete="off" />';
    $year_field   = '<span class="screen-reader-text">' . esc_html__( 'Year', 'learndash' ) . '</span><input  type="number" placeholder="سال" min="0000" max="9999" class="ld_date_aa ' . $field_class . '" name="' . $field_name . '[aa]" value="' . $value_aa . '" size="4" maxlength="4" autocomplete="off" />';
    $hour_field   = '<span class="screen-reader-text">' . esc_html__( 'Hour', 'learndash' ) . '</span><input type="number" min="0" max="23" placeholder="ساعت" class="ld_date_hh ' . $field_class . '" name="' . $field_name . '[hh]" value="' . $value_hh . '" size="2" maxlength="2" autocomplete="off" />';
    $minute_field = '<span class="screen-reader-text">' . esc_html__( 'Minute', 'learndash' ) . '</span><input type="number" min="0" max="59" placeholder="دقیقه" class="ld_date_mn ' . $field_class . '" name="' . $field_name . '[mn]" value="' . $value_mn . '" size="2" maxlength="2" autocomplete="off" />';

    $html .= '<div class="ld_date_selector">' . sprintf(
        // Translators: placeholders Month, Day, Year, Hour, Minute
            esc_html__( '%1$s %2$s, %3$s @ %4$s:%5$s' ),
            $month_field,
            $day_field,
            $year_field,
            $hour_field,
            $minute_field
        ) . '</div>';

    /** This filter is documented in includes/settings/settings-fields/class-ld-settings-fields-checkbox-switch.php */
    $html = apply_filters( 'learndash_settings_field_html_after', $html, $field_args );

    echo $html;
}

add_action(
    'learndash_settings_sections_fields_init',
    function() {
        LearnDash_Settings_Fields_Date_Entry::add_field_instance( 'date-entry' );
    }
);

/**
 * Updates the course access time for a user.
 *
 * @since 2.6.0
 *
 * @param int        $course_id Course ID for update.
 * @param int        $user_id   User ID for update.
 * @param string|int $access    Optional. Value can be a date string (YYYY-MM-DD hh:mm:ss or integer value. Default empty.
 * @param boolean    $is_gmt    Optional. True if the access value is GMT or false if it is relative to site timezone. Default false.
 *
 * @return boolean Returns true if the value is updated successfully.
 */
function ld_course_access_from_update( $course_id, $user_id, $access = '', $is_gmt = false ) {

    if ( ( ! empty( $course_id ) ) && ( ! empty( $user_id ) ) && ( ! empty( $access ) ) ) {
        if ( ! is_numeric( $access ) ) {
            // If we a non-numberic value like a date stamp Y-m-d hh:mm:ss we want to convert it to a GMT timestamp.
            $access_time = learndash_get_timestamp_from_date_string( $access, !$is_gmt );
        } elseif ( is_string( $access ) ) {
            if ( ! $is_gmt ) {
                $access = get_gmt_from_date( $access, 'Y-m-d H:i:s' );

            }
            $access_time = strtotime( $access );
        } else {
            return false;
        }

        if ( ( ! empty( $access_time ) ) && ( $access_time > 0 ) ) {
            // We don't allow dates greater than now.
            if ( $access_time > time() ) {
                $access_time = time();
            }
            
            $course_args = array(
                'course_id'     => $course_id,
                'post_id'       => $course_id,
                'activity_type' => 'course',
                'user_id'       => $user_id,
                'activity_started' => $access_time,
            );
            $activity_id = learndash_update_user_activity( $course_args ); 

//          return update_user_meta( $user_id, 'course_' . $course_id . '_access_from', $access_time );
            return update_user_meta( $user_id, 'course_' . $course_id . '_access_from', 'access_time' );
        }
    }
}