The problem is what the Ukrainians need is SPAAGs and air power; the Donbas is getting hammered because they have no AA protection at the moment.
They need those Polish MiGs, and they need them yesterday.
I highly doubt the quality is as good as that of the NATO countries and from what I hear, the time it takes to resupply is much worse then that if Western nations.I can't find the article anymore but there was a mention some years ago that russian peacetime production of artillery rounds from 120-152 mm outstripped production of artillery ammo in NATO countries from 105 to 155 mm by four times (don't know about rockets). Russia also still has considerable stockpiles, despite number of depots exploding and disposing of much of improperly stored ammo, while stockpiles in NATO countries are minuscule.
As in batches vs single rounds
Ukrainian is also more accurate