Running openvpn inside a docker container make network inacessible

Question

I have an app is dockerized, then I need to make this app work with VPN, so I need to install openvpn and run it inside my container. I use docker desktop for window 10. I have run these below commands:

1. Open first cmd, create a container: docker run -t -d --cap-add=NET_ADMIN debian:bullseye
2. Connect to my container: docker exec -it <MY_CONTAINER_ID> /bin/bash
3. Check my IP: curl ifconfig.me -> OK I got my IP address. It can connect to internet
4. Install openvpn: apt-get update && apt-get install -y dialog apt-utils && apt-get install -y -q --no-install-recommends openvpn procps curl
5. Create a /dev/net/tun device manually: mkdir -p /dev/net && mknod /dev/net/tun c 10 200 && chmod 600 /dev/net/tun
6. Copy my openvpn config file to container: docker cp test.opvn <MY_CONTAINER_ID>:/
7. Run openvpn: openvpn --config /test.opvn -> I got successful connection.
8. I open a new second cmd and connect my container again: docker exec -it <MY_CONTAINER_ID> /bin/bash
9. Check my IP: curl ifconfig.me -> timeout. So my container is diconnect from internet
10. Back to my first cmd. It is running a vpn connection in interactive mode. I cancel it by pressing Ctrl+C -> VPN disconnection
11. Back to my second cmd then check my IP again: curl ifconfig.me -> OK I got my IP address. It can connect to internet

I know the problem may be vpn server, so I try to test test.opvn in my laptop -> It work. Therefore, I think the problem may be vpn connection with docker, but I can't find solution, so please help.