Output a specific link in WordPress post if the single post’s category’s name contain certain word

I want to output a specific link in every post, depending on the post’s category. For example, If a post is in "travel" category, then the link to https://www.example.com/travelbooking will be displayed in this post. If a post is in "hotel" category, then the link to https://www.example.com/hotelbooking will be displayed in this post.

I tried this code

    <?php    $  category = get_the_category();   $  firstCategory = '$  category[0]->cat_name';   if (strpos($  firstCategory, 'travel') !== false) { echo '<a href="https://www.example.com/travelbooking">Visit travelbooking</a>'; }        if (strpos($  firstCategory, 'hotel') !== false)  {     echo '<a href="https://www.example.com/hotelbooking">Visit hotelbooking</a>';    }          else {      echo '<a href="https://www.example.com">Visit homepage</a>'; }       ?>  

But it doesn’t work, any suggestion?