It isn’t really. Even Russia itself does not believe that the current rate is “real”. If it was Russia would have used its rubles to buy euros/dollars to pay it

It isn’t really. Even Russia itself does not believe that the current rate is “real”. If it was Russia would have used its rubles to buy euros/dollars to pay its debt instead of defaulting by trying to pay with the rubble. Basically it is currently up artificially due to Russia buying rubbles with dollars/euros/gold/etc (and 20% interest rate) and them themselves pushing it the other way by trying to buy dollars/euros with rubbles would be counterproductive.