Override WooCommerce email order template for admin to show start link

functions.php

<?php 

add_filter( 'woocommerce_email_order_details', 'email_order_details_20221128', 1, 4 );
function email_order_details_20221128( $order, $sent_to_admin, $plain_text, $email ) {
	$GLOBALS['zoom_sent_to_admin'] = $sent_to_admin;
}

add_action( 'vczapi_woocommerce_order_item_meta', 'custom_order_meta_20221128', 99, 4 );
function custom_order_meta_20221128( $content, $item_id, $item, $order ) {
	$sent_to_admin = ! empty( $GLOBALS['zoom_sent_to_admin'] ) ? $GLOBALS['zoom_sent_to_admin'] : false;

	if ( $order->get_status() === "completed" || $order->get_status() === "processing" ) {
		$product_id = $item['product_id'];
		$post_id    = get_post_meta( $product_id, '_vczapi_zoom_post_id', true );
		if ( ! empty( $post_id ) ) {
			$fields          = get_post_meta( $post_id, '_meeting_fields_woocommerce', true );
			$meeting_details = get_post_meta( $post_id, '_meeting_zoom_details', true );
			if ( ! empty( $meeting_details ) && ! empty( $fields['enable_woocommerce'] ) ) {
				$tz_for_check     = new DateTimeZone( 'UTC' );
				$dateTimeTomorrow = new DateTime( 'NOW', $tz_for_check );
				if ( ( true == apply_filters( 'vczapi_woocommerce_show_past_meetings_in_account_details', ( ! empty( get_option( 'vczapi_wc_hide_completed_meetings' ) ) ) ) ) && $meeting_details->type != 8 && $meeting_details->type != 9 && $meeting_details->type != 3 ) {
					$meeting_date_to_check = vczapi_dateConverter( $meeting_details->start_time, 'UTC', false );
					if ( $dateTimeTomorrow >= $meeting_date_to_check ) {
						return;
					}
				} elseif ( ( true == apply_filters( 'vczapi_woocommerce_show_past_meetings_in_account_details', ( ! empty( get_option( 'vczapi_wc_hide_completed_meetings' ) ) ) ) ) && ( $meeting_details->type == 8 || $meeting_details->type == 9 ) ) {
					if ( class_exists( 'Codemanas\ZoomPro\Helpers' ) ) {
						$last_occurrence       = end( $meeting_details->occurrences );
						$meeting_date_to_check = vczapi_dateConverter( $last_occurrence->start_time, 'UTC', false );
						if ( $dateTimeTomorrow >= $meeting_date_to_check ) {
							return;
						}
					}
				}

				ob_start();
				?>
                <ul class="vczapi-woocommerce-email-mtg-details">
                    <li class="vczapi-woocommerce-email-mtg-details--list1">
                        <strong><?php _e( 'Meeting Detailsssss', 'vczapi-woocommerce-addon' ); ?>
                            :</strong></li>
                    <li class="vczapi-woocommerce-email-mtg-details--list2">
                        <strong><?php _e( 'Topic', 'vczapi-woocommerce-addon' ); ?>
                            :</strong> <?php echo $meeting_details->topic; ?></li>
                    <li class="vczapi-woocommerce-email-mtg-details--list3">
                        <strong><?php _e( 'Start Time', 'vczapi-woocommerce-addon' ); ?>
                            :</strong>
						<?php
						echo vczapi_dateConverter( $meeting_details->start_time, $meeting_details->timezone, 'F j, Y @ g:i a' );
						?></li>
                    <li class="vczapi-woocommerce-email-mtg-details--list3">
                        <strong><?php _e( 'Timezone', 'vczapi-woocommerce-addon' ); ?>
                            :</strong>
						<?php
						echo $meeting_details->timezone;
						?></li>
                    <li class="vczapi-woocommerce-email-mtg-details--list4">
						<?php if ( $sent_to_admin ) { ?>
                            <a target="_blank" rel="nofollow"
                               href="<?php echo esc_url( $meeting_details->start_url ); ?>"><?php echo apply_filters( 'vczapi_woocommerce_start_via_app_text', __( 'Start via App', 'vczapi-woocommerce-addon' ) ); ?></a>
						<?php } else { ?>
                            <a target="_blank" rel="nofollow"
                               href="<?php echo esc_url( $meeting_details->join_url ); ?>"><?php echo apply_filters( 'vczapi_woocommerce_join_via_app_text', __( 'Join via App', 'vczapi-woocommerce-addon' ) ); ?></a>
						<?php } ?>
                    </li>
					<?php if ( empty( $disabled ) && ! empty( $meeting_details->password ) ) { ?>
                        <li class="vczapi-woocommerce-email-mtg-details--list5">
							<?php echo \Codemanas\ZoomWooCommerceAddon\DataStore::get_browser_join_link( $post_id, $meeting_details->password, $meeting_details->id ); ?>
                        </li>
					<?php } ?>
                </ul>
				<?php
				return ob_get_clean();
			}
		}
	}
}