The Ukrainians have been conservative with all their SAM systems.
The Ukrainians have not been conservative with anything. They have blown through all the equipment that the western allies could give them. They are low on just about everything to do with air defense, and what's left is in good part reserved for Kiev. They are low on just about everything to enable their ground forces to wage war effectively. It is sort of what happened to the Confederate army at the end of the Civil War. In addition to a shooting war, there is a war of logistics.
How much did they lose during the counteroffensive last year? It'll be interesting to compare that to Gettysburg.
The western allies havent given them much vs their needs, which are great given that they are facing a numerous enemy.
Ex - They have all of three Patriot batteries (18 launchers plus 4 spares, of which they have lost 1 or 2). The US has @1000 Patriot launchers, active or reserve.
They have received all of 30-odd GMLRS launchers, HIMARS or M270. The US has @1500 of these.
You have to look at the numbers. Do not assert things without facts.
Given their situation they have been very conservative from the beginning.