Certainly Russia's economy has difficulties. It has inflation roughly 9-10% and (dangerously low) unemployment around 1%. Russia's Central Bank key rate needs to be extremely high to fight its inflation because it is not as primary a lender as the US Fed for example - there's way more private lending. The inflation is caused by raising labor costs (due to unemployment), supply chain disruptions from sanctions, and weakening of the ruble due to printing of money to fund the war.

Thus far Russia's economy has grown substantially due to the war - expansion of its industrial base. This is factoring inflation in. What's happening right now is that Russian economic growth due to military industry is slowing down, and Russia is not likely to continue growing its economy at near the same rate.

Russia is most likely heading into an era of stagflation (high inflation and low growth). This isn't a collapse of the economy. It's not great, but its not a way to end the war.

One option could be to tank oil prices (into the $40/barrel range, currently $70/barrel range) and keep that for years. Due to Russia's reliance on energy income this would disrupt the Russian budget and it would either need to cut social spending or go into debt (e.g. to China) to continue without shelving social programs.

The point is that the Russian economy isn't on the brink of collapse. Due to the national security nature of a hostile military alliance at its doorstep, it's likely to make hard choices if put into such a situation (e.g. go into debt).