Putin will not run out of money, he can always use the Stalin method: Holodomor - steal from any of the non-Russian regions and use it.
This what happens in LDPR right now. Today I found out that some farmers I know run out from Luhansk because there no more even opportunity for peaceful life (even if we would ignore artillery and rockets). "Government" of LDPR expropriates resources from farmers because of "war situation". Farmers are told to sell their harvest for "fixed price" (less than they could sell it on market, ofc). And even after that "fixed price" farmers should pay taxes (around 50 % of income).
I hope that this will be extrapolate to all russia in near future.