First, it is the right of the Russian government to decide whatever the payment tool for their gas or oil. They are the seller, so it depends on them to accept whatever payment tool they want.
Second, I don't see that stable coins are better than BTC. If we look at the security of BTC and stable coins, I assume BTC is safer as it is the number 1 crypto coin. If the Russian government doesn't like its volatility, they can convert it to their currency and not hold a long time. Nothing wrong with BTC and we actually can deal with the volatility.
How do you know Putin has no good exchanger?
Once he decides to use BTC as the payment tool, he must already know well how it works and how to exchange it in a secure way. Putin is a smart person, you don't need to doubt his knowledge or his capability about crypto. And he shouldn't do it himself, don't forget that he is a president.
Putin is just puppet.not smart just puppet his masters are smart