Most secure would be Qubes VMs. I use pfSense VMs in VBox. So nested VBox internal networks (yes, multiple NAT) leads produces nested VPN chains.
Also, you can include a Debian VM running Tor and OpenVPN in a chain. You configure OpenVPN in TCP mode with "socks-proxy 127.0.0.1 9050". So you can route through 2-3 VPNs, then Tor, and then 1-2 more VPNs.
Or you can include a Debian VM that crudely emulates Tor (very crudely) by periodically switching among random chains of multiple VPNs.[0]
Also, you can include a Debian VM running Tor and OpenVPN in a chain. You configure OpenVPN in TCP mode with "socks-proxy 127.0.0.1 9050". So you can route through 2-3 VPNs, then Tor, and then 1-2 more VPNs.
Or you can include a Debian VM that crudely emulates Tor (very crudely) by periodically switching among random chains of multiple VPNs.[0]
0) https://github.com/mirimir/vpnchains/