1. The long term contracts are in USD / EUR not Rubles, you cannot change the currency without renegociating the contracts. Hence the Buyer -> Gazprombank (EUR -> RUB) -> Gazprom schema companies are using. It`s not paying in Rubles.
2. Russia needs to buy medicine or non santioned components with USD / EUR. The sancions are not a trade embargo. Russia is very import dependent.
3. Russia just put a Gas embargo on Poland and broke contracts. This massivelly improved the perception of Russia. The game is to lure Russian to put embargos on other countries and by this force sanction it self