How to create a proxy server?

Question

proxy

Hey guys. Point in the right direction, you need to implement the chain Client => Proxy 1 => Proxy 2 => Server. All proxies have their own Basic authorization. I don’t understand how to do everything right, because proxy 1 adds the Proxy-Authorization header, and it seems like you can’t change the request in HTTPS (only if you put the root certificate). Where am I going wrong and what can be used (libraries)? No need to sniff traffic)