I use a card for the first one because it's gotta know my IP, and my ISP can link me to my IP.
Nothing can protect from adversaries with a global view of the internet. At least, for low-latency activity. If the latency is high enough, and there's lots of chaff, there's maybe a chance. Or at least, there are too many false positives to deal with.
Otherwise, you just make it harder. Once you have more than a couple VPNs in a chain, and especially if you switch chains frequently, latency varies a lot. So that likely helps too.
Edit: There is nothing in OpenVPN about routing one VPN through another. That's all done in the host networking stack, or using multiple routers with NAT forwarding. There is, however, a SOCKS5 proxy option, which you can use to route a VPN through Tor. Or you can just run a VPN server as an onion service.
Nothing can protect from adversaries with a global view of the internet. At least, for low-latency activity. If the latency is high enough, and there's lots of chaff, there's maybe a chance. Or at least, there are too many false positives to deal with.
Otherwise, you just make it harder. Once you have more than a couple VPNs in a chain, and especially if you switch chains frequently, latency varies a lot. So that likely helps too.
Edit: There is nothing in OpenVPN about routing one VPN through another. That's all done in the host networking stack, or using multiple routers with NAT forwarding. There is, however, a SOCKS5 proxy option, which you can use to route a VPN through Tor. Or you can just run a VPN server as an onion service.