They've migrated to a wartime economy, which gives you a lot of command over the economy. They're currently doing a careful dance of increasing their money supply, while trying to stabilize inflation using what foreign currency reserves and income they have.
The biggest thing keeping their economy going is the price of oil, which is hovering around 80-90$ a barrel. The vast majority of this is being gobbled up by the government via their national wealth fund.
So long as heightened domestic productivity is maintained for the war, and the price of oil is higher than 60-65$ they could retain solvency for years.
A real economic collapse won't be felt until the price of oil bottoms out, or if they attempt to transition out of a war time economy.
The key point about wartime economies is that they don't actually increase quality of life for the people, even if everyone is making a decent salary (by Russia standards anyway).
Public infrastructure in Russia was already struggling before the war, I can only imagine the state it'll be in in 10 years
I looked at one of those ship monitoring sites and there was almost a continous string of oil tankers going to and from St. Petersburg, so I'd say they're probably selling a fuck ton of oil still.
Money doesn't come from the US. It is a derivative from people going to work and banks borrowing from future generations to give more money to the supremes and the billionaires. To make one billionaire all you gotta do is borrow from several generations ahead. So don't get angry if the inflation is high. That's something that paid for billionaires before you were born. Nah. This is so that your kids can't have a house and same for their kids and kid's kids. It's great 👍.
They have a lot of natural resources and are selling them still (China as you said, India). Plus it's not like people will complain if inflation is high, or road don't get repaired.
I guess this stuff was already in their inventory so using them isn't going to cost them a dime? Replacing them, on the other hand, could be a problem.