The scoring function is wrong, checking for white is not as simple as calling contains. if guess[i] == secret_code[i]: red += 1 else: if guess[i] in secret_code: white += 1 With the secret XXXY a guess of YYYY will be scored as one red and three white but it should be just one red. You have to keep track of which positions in the secret have already been consumed, in this case the Y in the secret gets consumed by the…
Wordle programs often start with a similar bug in their (similar) scoring function. Apart from tracking positions and consuming them as you suggested, there's also another approach to writing the scoring function, suggested by Knuth's notation in the paper mentioned in another comment:
from collections import Counter
def score_guess(guess, secret_code):
red = sum(guess[i] == secret_code[i] for i in range(len(guess)))
total = (Counter(guess) & Counter(secret_code)).total()
return (red, total - red)
assert score_guess('YYYY', 'XXXY') == (1, 0)
assert score_guess('YYYX', 'XXXY') == (0, 2)