As for payments in roubles, they made export companies to sell 80% of foreign currency got with export revenue before plans on selling anything for roubles. So the difference between 80% and 100% is not so big. Yes, it helps with the rouble rates but it is far from market situation.
Main problem for government for bypassing sanctions with crypto is not only that it can destroy the money value of rouble, it can be hardly done as Russia is a big country with a huge import volume. Even if it can get enough crypto for trading (which is hard by itself as all amount of crypto holded by Russians is just about 100-130 billions of USD
according prime minister Mishustin) it is impossible to import such volumes of goods into the country unnoticed.
Russia is basically going for the short term solutions and that is not a bad thing when you are a whole nation in war because during the war times you could have radical short term solutions. In the end, we are going to have something that will be a bit more at ease and people will like it for sure.
What we need to realize is that the best thing we can do right now is to keep the sanctions against Russia, keep putting more money in renewable energy which will not only allow nations to be energy independent and not need sources from Russia but also it would help the climate as well, then hope that the war doesn't go for long and threaten Russia with these.