Russia has many options that can be used to avoid sanctions. Using any payment method other than the dollar would be appropriate, and then we would find that local currencies or exchanges for oil/food would be more effective than the dollar.
Bitcoin may be an option, but I do not see that there is anything special about Bitcoin that will make the government adopt it.
The effect will be for individuals to buy Bitcoin, changes will happen, especially if governments decide to impose restrictions on deposit withdrawals or at least the currency depreciation.
I agree with your point, as they're accounting for 17% of the world's natural gas and 12% of its oil if they go for other local currencies in exchange there might be a chance to avoid sanctions.
But I don't think Bitcoin would be an option because as they're dealing in a huge scale they'll prefer stable currencies, because they cannot do a sudden shift to bitcoin as it is very volatile!
They can legalize crypto by introducing their own crypto in to the market and imposing tax on other crypto currencies like how India did recently.
And I dare say one more thing, US and EU will not exclude Russia from the SWIFT alliance. Russia is the main oil supplier to the US and EU countries. if US and EU exclude Russia from SWIFT, they are pushing Russia towards China, I don't think they will be that stupid.
Russia is the 4th largest gold and foreign currency reserve country in the world, it has a lot of opportunities to avoid sanctions. Many hypothesize that they will use bitcoin to fend off sanctions. bitcoin is good but with volatility and manipulation not the ideal choice to save a country's economy.