Add multiple meta keys to a post at once

As @milo was saying above each value that you wish to save as post meta will need it’s own call to update_post_meta. And each usage of update_post_meta will need you to specific a unique name for that meta value.

Since you have all the data in an array and you have already sanitized it you could do something like this:

foreach( $data as $key => $value ) {
  update_post_meta( $post_id, $key, $value );
}

that will loop through the array and save each value and set is meta key/name to the array key you set previously in your code.

So this should work for you, but I would say that it might be worth looking at your code more to ensure all data is present before looping through the data array.