OpenVPN behind Nginx reverse proxy

I have an OpenVPN server on a machine that can only be connected to via IPv6, due to my ISP being not too generous with IPv4 addresses.

To resolve this issue, I created a DigitalOcean droplet, installed Nginx on it, with the purpose that I'll use the droplet to forward any incoming IPv4 traffic to the aforementioned server through IPv6.

I know that the connection between the DO droplet and my server is fine, because I could connect to my home server via SSH and OpenVPN as well from the droplet. My problem is, whenever I'm trying to connect to the home VPN from anywhere, through the DO droplet (as originally planned), it seems like the connection gets lost somewhere, according to the OpenVPN client log Sat Apr 20 23:03:02 2019 read UDP: Unknown error (code=10054).

I also know that the connection between the desired vpn client and the droplet is working, because I can SSH into the droplet machine from that. I also checked the firewall ports and the required port is open with the required protocol.

So in theory, both part of the connection should be fine, but I still get the network connectivity error. I tried lots of different ways to configure nginx, but none seems to work.

TL;DR

I'd like to use a tunnel to forward my IPv4 requests to a server accessible from IPv6 only, but I connection is lost somewhere on the way.

My Nginx config:

stream{
    upstream backend {
        server [2a02:ab88:5081:7e00:b4b6:fef2:5742:b12f]:1194;
    }

    server {
            listen 1194 udp;
            proxy_pass backend;
    }
}

I've been trying to solve the issue in question for a couple of hours and right after I submitted the question, I managed to solve it.

The solution was not done with Nginx, but with socat. The command is simple and self describing: socat UDP6-LISTEN:1194,fork UDP6:[2a02:ab88:5081:7e00:b4b6:fef2:5742:b12f]:1194