Creating Proxies from Proxies/VPN on a Windows PC

[svstels]

Hey everyone!

I'm tired of brainshtoring this with GPT and Gemini. Now I'll be happy to talk with real people!

The problem. I have a VPN provider and want to create 10 connections and use them as an Internet source for local proxies created by local proxy server. Also this VPN provider has a Google Chrome extension which can connect via Google Chrome's standard proxy settings via extension with: host, port 443, https protocol, username and a password. You can think now that is the solution but this proxy server works only with Google Chrome.

What I've tried:

1. Different proxy server apps for Windows. But they can't use upstream proxies with the same address and credentials I described before. I believe it is because Google Chrome's proxy connection protocol is different. Maybe I haven't used exact proxy server software which can work as Google Chrome? Please if you know one, let me know!
2. Creating multiple VPN connections on a PC and then trying to use these connections as proxies with c# app I created. But the thing is routing. I can create 10 VPN connections but when routing comes into place it all becomes very messy. If they don't have an access to the internet, everything's fine. But when I start adding 0.0.0.0 route to them, some websites use VPN connection, some websites user my main LAN connection. It's very unsustainable.

Ideally I want to have a software that will connect to a proxy as Google Chrome does (use my VPN provider's proxy as an upstream proxy) and then create proxy server from this connection.