Earlier quoted context omitted.
> Always block China and Russia from any of your services. But does this add much security if bad actors are using VPNs ?
They'd need to run a VPN with end point in a less hostile country and so there's an element of enforcement on those endpoints. At any rate, blocking China and Russia isn't ever presented as a foolproof defence, it just raises the barrier to attack.
Either way, nothing is full proof. It is part of a solid defense in depth [1].
[1] https://en.m.wikipedia.org/wiki/Defense_in_depth_(computing)