IMO, if the oil prices plunge then the chances of war should decrease. The Saudis are able to make their multi-billion USD defense purchases, only when the oil prices are high. If the brent crude plunges below $20 per barrel and stays there for a few months, then these people would be forced to cut back on their foreign interventions (especially the invasion of neighboring Yemen).
Besides the declining demand due to the coronavirus epidemic, in my opinion, the oil price war between Saudi Arabia and Russia is only a proxy war run by the United States through MBS to tackle Russia but it seems that Russia is not afraid of the bluff of MBS instead the United States and Saudi Arabia are now doing lobbying to President Putin. Trump took the initiative to call Putin and the two agreed to hold a repeat discussion about oil prices.
The bluff done by the United States to Russia failed miserably because, there was no relaxation at all regarding Russia because Putin's main goal was not just oil but with his bargaining power, Putin wanted the United States to reduce sanctions to several Russian allies such as the Nord Stream 2 pipeline. connecting Russia to Germany then the Rosneft agreement in Venezuela. In addition, Russia needs a market share captured by American shale oil back to Russia.
Now the choice is in Russia's hands, it will punish the US shale oil industry to stop or file sanctions for the United States.