Control of the DHCP server in the victim’s network is required for the attack to work.
This is not a VPN vulnerability, but a lower level networking setup manipulation that negates naive VPN setups by instructing your OS to send traffic outside of VPN tunnel.
In conclusion, if your VPN setup doesn’t include routing guards or an indirection layer, ISP controlled routers and public WiFis will make you drop out of the tunnel now that there’s a simple video instruction out there.
This is blatantly false. They can see IP addresses and ports of you connect to from IP packets, and hostnames from TLS negotiation phase (and DNS requests if you don’t use custom DNS settings). HTTP data is fully encrypted when using HTTPS.
If exposing hostnames and IP addresses is dangerous, chances are that establishing a VPN connection is as dangerous.