It was a very big mistake of many European countries to become dependent on Russian gas and oil. They cannot resign from importing overnight, but the European Union has already introduced laws reducing imports from Russia. Russia will be losing customers and shortly will no longer have enough income to cover the cost of the war. We also, can limit tax revenues from Russian casinos by boycotting them. It may not be much, but if we can help shorten this war, why not do this?
It wasn't expected, that's the problem. They were already focusing on becoming energy self sufficient by 2030 to 2035 between each other, that was good enough for them and they didn't really consider there would be a war that would cause this to get quicker. In the end, the war happened in 2022 and now they are holding their money in their hands.
If they pay Russia, which they have to, then they would be basically financing Russia to attack Ukraine, if they pay Ukraine then they are paying it with the Russian oil they used to make that money, all in all it is not a good decision and they will end up with some problems and that's why I believe it is not going to be easy.