I don't read any Russian media - do you really believe everything you read in the British media?
I do. Your claims are pretty much word-for-word what's coming out of Russian media outlets, even down to the wild claims that Russia is thriving while the West suffers.
Russian energy is finding plenty of customers to replace the economically declining west. They may have to discount to begin with but they're not selling at a loss.
They are finding customers at a substantial discount. From what I remember, it costs around $45 to produce a barrel of Russian oil, and it's believed that it's being sold for $70 to India. That's not great business, especially when you consider the price that they could be getting elsewhere. Furthermore, it makes them dependent on a very unpredictable partner. China will buy, but this is the last thing that Russia needs: being economically dependent on China, especially given the Chinese patience and ability to play the very long game.
Overall increasing world prices for energy can only have the effect of bolstering energy exporters of which Russia is one of the largest.
The US led attempt to put an "Oil price cap" in place is failing miserably.
One other problem is that Russia needs Western technology in order to extract and actually deliver the oil in question.
As for military industrial capacity the proof is in the pudding. The Russians appear to have the capacity to produce virtually limitless quantities of shells and missiles - many of them as advanced or even better in performance than the west's. If you're looking for an industrial economy in it's last throes - just look about you.
That is very much fantasyland stuff. They might be able to produce shells and missiles without any real technology, but those are useless in modern war. All they can do is terrorise civilians, but they won't be able to accurately strike UAF positions with them. The modern stuff requires - again - Western technology, and they don't have it. More to the point, if they *had* such technology, why are they resorting to flinging ancient missiles at Ukraine?
Yes they are having to change where they're sourcing some industrial products including commercial airliner parts (they are after all under a form of blockade), in this they are being assisted by many countries not least China but also by NATO member Turkiye, and this process is proceeding rapidly.
They are trying to source them, but China has no interest in helping them for various reasons. Turkey is also not helping them with such parts, and in fact, Turkish Airlines has taken advantage of the situation to buy Aeroflot's undelivered A350s. That means the only option is to manufacture the parts themselves, but again, they don't have the capability to do so. A good example is with aircraft tyres, which Russia doesn't produce. They will probably be able to create something that works, but it won't be anywhere near the standard of what the West produces. That means blowouts on takeoff/landing, and with it, a higher risk of crashes.
The situation is also critical because Russian companies (using Western technology) were supplying countries such as India. Now, India has turned round and said that they want to be self-reliant, so they're going to cut Russia out of the loop when it comes to military purchases. That means less money in Russian military companies, which in turn means less money to replace Western technology. Russia is essentially heading back to the 1970s in terms of technology. The cars, the military equipment, the planes, everything is headed back to an era where the West will leave them far behind.
It's notable that Putin has signed some kind of order meaning that the economy is now on a war footing. People can be taken from their work and made to work in military production instead, which strongly hints at them not only having supply issues, but also having to move towards labour-intensive activities. That means less labour in the real wealth-producing economy, and so living standards will fall further.
Just one example: the local Tinkoff Bank in Russia will start to charge 1% in fees in Forex accounts. The same bank has empty ATM machines, and this leads to the key problem: the ruble is strong because they simply aren't spending foreign currencies. They're earning a lot of it, but it's not being spent, and so the ruble continues to strengthen. The problem is compounded by the fact that there's nothing really much to buy, because of the sanctions. It's also very difficult to actually buy rubles on the market, so what you're dealing with is an exchange rate that bears no relation to reality.
The latest suggestion is that Russia will start buying currencies from countries that they have friendly or neutral relations with. That means buying up the Indian rupee, the Chinese yuan and so on. Does that really help Russia? Nope.