We can assume that all (Kremlin) numbers on the Russian economy are doctored to make people believe that Putin can fight this war for years and years to come.

AFAIK there is some solid open source intelligence out there, suggesting that russian economy is dire in some sectors. Prices for consumer goods are the easiest example here.

You are right in that war makes the economy go brrrrrt in some sectors but the money spend there is thrown out of the window. Every person who works to build new tanks is a person less to maintain bridges, roads and infrastructure in the oil and gas industry.

And when it comes to government spending in Russia, it means a lot of corruption will be happening and money flows to the top.

Every soldier on the frontline is a farmer or woodworker less back in mother Russia. Families lose their main income when the father dies, even though the mother spend their last savings on a bullet proof vest that was at some point imported from China.

You have to keep in mind that the Russian economy is comparable to Italy or the Netherlands. The impact of the war on EU countries isnt noticeable compared to that. At worst, it gives us problems that we can easily solve with money.

Another thing about Russia is their demographic. They will lose and already lost a lot of their most productive workforce. Additionally a lot of young and well trained men left Russia in the last two years. Even more try to stay in the university as long as possible to not get drafted.

Russia is so fucked man!

[Edit] lot of words

Not even close, Russia still has capital controls and an interest rate of 8.5% hardly the same level of bad. Recently has started to seizing assets from Western companies, if the trend continues will need to see how far they will go.

Making something seem resilient and successful is very easy in the short term when you have control over what data is coming out of it.

There were companies that were commiting fraud or were straight up ponzi schemes that seemed very successful, all while operating under some oversight from the western governments and the public. Some lasted many years before the facade crumbled and they collapsed.

Now imagine what an entire corrupt government with full control of the reports, the media and no one to answer to, is capable of.

Using resources on a war does stimulate the economy. That's just the Broken Window Fallacy.