Proton VPN is a VPN service, InviZible is partly a Tor / I2P client. They're quite different.
Both apps have some degree of DNS filtering features already. Rethink DNS should only really come on your mind if you are trying to filter something unique, because it could stand out that you do filter something the others do not.
You should look into whether using a network like Tor is right for you first, because they should be used differently and it is also much slower.