How can steam identify the parser?

Question

Python

There is a bot that parses the Steam site. Of course, periodically flies to the ban with the code 429 (many requests). Steam retry-after does not give out, you have to guess the time blindly. I connected tor with privoxy and through them I start parsing. If you change the IP for each request, then Steam does not identify it, but it is too time consuming. If you change the IP immediately after the ban, then Steam even under a different IP identifies the parser and bans again, how so?

session = requests.session()
proxies = {"http": "http://127.0.0.1:8118",
           "https": "https://127.0.0.1:8118"}
cookies = {'Steam_Language': "russian"}
headers = {'user-agent': UserAgent().random}

def get_html(url):
    global session, headers
    while True:
        html = session.get(url, cookies=cookies, headers=headers, proxies=proxies)
        time.sleep(random.choice([0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7]))
        while True:
            if html.status_code == 200:
                return html
            elif html.status_code == 400:
                return None
            elif html.status_code == 429:
                CM().new_identity() #  смена айпи
                session = requests.session() #  смена сессии/подключения
                headers = {'user-agent': UserAgent().random} #  смена юзер-агента
                time.sleep(random.randint(6, 14))
            else:
                return None