The problem is Russian decision to go with the Iskander design. Not that Iskander is a bad missile, quite the contrary it is actually top of the line for this range class. That is the precise issue. It's state of the art status, makes it a expensive and time consuming production process. You will run out quickly if used aggressively.
Quantity prevails here. This is really a matter of doctrine. Perhaps another simpler design should have been produce alongside Premium weapons like Iskandar. Something to use in areas where their are little ability for AD to target. Well protected targets can use Islanders.
I’m glad Iran has moved past the quantity stage of missile development and is now firmly committed to the improvement quality/combat effectiveness of its arsenal outside of just sheer numbers.
It’s good to fire thousands of ballistic missiles but you still need those highly lethal, very accurate and capable weapons that can get past even the most comprehensive of enemy ABM shields.
On the topic of BM use in the theatre of war. IRGC missile forces would be the best suited force on the planet for such a striking regime along with their massive inventory of long-range drones. The BM would easily be able to knock out 100s upon 100s of targets overnight depending on the scope of operation for the fire mission and the drones would mop up whatever is left.
The only issue here is ISR.
In a hypothetical scenario: Iranian land forces would probably be badly beaten by Ukrainian troops, but Ukrainian assets (especially stationary ones) would be virtually wiped out in several weeks or less. All totally dependent on just how comprehensive Iranian planners are in what to strike.
ABM shields, even NATO ones can’t keep up with the massive rate of fire IRGC missile forces can launch.