Why isn't Russia going bankrupt?

Apparently the war costs Russia $20 Billion a day, and assuming that half of Russias $630 Billion foreign reserve remains frozen - russia only has reserves for two weeks of war. One of which is already over.

Obviously, Russia also has a acces to rubel reserves. But you also have to consider that the aftermath will also cost Russia a lot if they want to achive their goal (an independant Ukraine). If Ukraine ties itself to the EU to finance rebuilding, that would kinda miss the point of the whole invasion.(Comparison: Rebuilding Donbas alone was estimated to cost $20 billion - even without the additional damage of the invasion). So I'm just ignoring that and say thats the money is allocated elsewhere.

I guess Russia is largely self-sustaining regarding the most basic needs (food, water, energy), but rebuilding the army after the war seems like it would eat all of russias reserves. All that wouln't really be a problem if Russia would amass debts like any other country - but I can hardly see anyone willing to lend them money to rebuild their army?

TLDR: The numbers above seem to align with articels like this, claiming the war is over after 10 days. But the majority of news claim the sanctions don't hurt Russia (shortterm) and the war might go on for a long time still. How is that possible?