They bought Shahed drones from Iran and an undisclosed cargo from North Korea specifically to avoid further depletion of their national stockpiles. They can't commit everything to Ukraine because they still need to maintain a certain level of readiness all over the nation.

Institute for the Study of War assesses their stockpiles of precision ammunition as dwindling. They seem to be making deals with Iran for increased ammo and drones, in return for cash and captured western/Ukrainian arms technology, as well as potentially help with their nuclear weapons program and geostrategic partnership on an equal footing.