Authorization on the site using the POST request method and a unique generated key?

Question

HTTP headers

Hello. I've been trying to authorize on one site for a month now using traffic analysis (Http headers).
I ran into some problems that I still can't solve. Having studied a lot of information on the Internet, both in the ru segment and in the en segment, I did not find any information, only superficial.

In this connection, I have 2 questions: when analyzing traffic and during authorization, many redirects are sent, to third-party servers of the project on which I am trying to perform authorization, are there any applications that will help to more clearly track the necessary redirects (developer tools with this do poorly)? And the second most important question: during authorization, a unique signature key is generated, for one request, I tried to parse it from other requests, but it is unique only for one request, for others it is completely different, is it possible to authorize through requests in this case and how its best to mate?
Are there people who are well acquainted with the capture and analysis of traffic and who could help me individually, for a fee?