Well, RF (30% of market share) did
not decrease the supply, it was the demand that rose "unexpectedly". Well, why did the US not rescue the EU with additional supplies of LNG, for example? The gas terminals were built several years pretty much for this reason, to be able to buy LNG from the US and Qatar to diversify the supplies. Why did Norway with its 35% market share not increase the supply via
its pipelines? Nope, it is Russia that must increase the supply, apparently to the level of having about 50% of market share, but that would be fine this time because... reasons?
Also, RF resisted until the very last from switching from the long-term contracts to the spot contracts, it was forced to do so by the court decision in 2019, sued by Poland that argued that the spot market price is fairer (it also got $2 billion refunded to the boot). Two years later, this November, Poland tried to sue again, arguing now that the spot market price is unfair, and Gazprom should only take the previously negotiated price, and refund whatever was overpaid to it (about $5 billion IIRC).
I understand that all this is pretty much how haggling looks like when the hagglers are nation-states who have to sell the deals to their population somehow: selective reporting, overstating some circumstances, understating other, selective application of arguments, etc. But the end result is still exorbitant heating/electrical bills and cold houses all over the country but you also get to feel outraged at the other side, as a bonus.