backconnect proxy server

Hi, have you experience in backconnect proxy server?

I want a backconnect proxy server that create sock5/http proxy
the client connect to these proxy to access to the backconnect proxy server
all customer connect to the same backconnect proxy server, it's like a gate
and depends on the customer order, the backconnect server would assign a proxy in the pool
the pool of proxy can have France, UK, spain, US proxies, with different rotation time
so if a customer order a UK proxy, his system connects to the backconnect server and the backconnect server redirect request to a UK proxy.
If the customer want a 10 minutes rotation UK proxy, through a customer panel, he choose what he wants, the ecommerce website create a backconnect proxy
the customer enter the proxy in his sytem
his system connects to the backconnect proxy server which knows that the customer want a 10mintes rotation UK proxy, then redirect his trafic to a 10minutes UK proxy
if this 10minutes UK proxy doesn't exist or not available, in this case in the client panel, the customer cannot select 10minutes UK proxy before, or the ecommerce website shows out of stock or not available

links to check
https://ldg.io/blogs/backconnect-proxy-pt1
https://github.com/LegionDevelopmentGroup/blog.examples.backconnect_proxy