To get the resultant URL after you’ve been redirected, you can do r.url.
r = requests.get('https://youtu.be/dQw4w9WgXcQ')
print(r.url) # https://www.youtube.com/watch?v=dQw4w9WgXcQ&feature=youtu.be
r.history is for URLs prior to the final one, so it’s only returning your original URL because you were only redirected once.