Vpn network proxy service

[openwrticon]

Hi, I have a VPN (openvpn client) connected to a VPN provider. Not all wan traffic is routing through VPN.
I can route traffic to VPN with PBR and it works great for specific devices/IPs.
How can I setup a SOCKS5 proxy that will route its incoming traffic through VPN?
(So I can instruct firefox to use that proxy whenever I want VPN services)
I want something like this:

Network wide VPN for specific services over a Proxy

This image will hopefully clarify what I'm trying to achieve: [Untitled-1] The service allows for a connection with a Proxy Server via SOCKS4, SOCKS5 and HTTP. Would my idea work in this case? Or is there a more suitable solution for my purpose?

where the 'private service' is a firefox profile.

[trendy]

I don't see why not, if the default action is to use regular ISP and the proxy is using by default VPN.

[openwrticon]

How can I create a proxy for this?
by which program?
(edited original post for clarification)

[trendy]

Dropbear can act as socks5 if you enable gateway ports.