Also, the fact that Russia is refusing to sell gas to the EU because of its support for Ukraine rather undermines this point. (I think it's the EU that should be refusing to buy gas from Russia in order to stop funding the Russian war machine, but it's interesting that both sides don't want to trade right now.)

If Russia really wanted to prevent Ukraine or the EU from having access to resources in Donbas or Crimea, shouldn't they be using their current control over those areas to ruin/destroy those resources or make them harder to access?