Well, the core of the usage of HIMARS or MLRS system like that is to disrupt your enemy logistic.
First of all, there are virtually no way you can stop Russian from launching Artillery Attacks, as long as they have rounds and tube, they will continue to be doing so, the question now become how you can mitigate such attacks.
Now, you can do it in one of the two ways, target the main supply effort (or Main Line of Communication)or disrupt their region supply depots (The one that serve the immediate area). Both are each of their own. As I mentioned before, if this was me, and when I get my hands on MLRS like M270 or HIMARS, I will go after their Main Line of Communication (Kupiansk) , because you disrupt the normal flow of supplies, it will not stop the onslaught for now, since the "Ready to Use" stuff are already distributed, but it will hamper the supply effort, effectively your line of supply will be interrupted and will have a hard time filtering supply. That's very simple, you disrupt the supply coming from Russia, you increasingly lower the amount that supply get to the front.
What the Ukrainian is doing is the other way, they are targeting the regional depots. Which make immediate disruption to the Russian supplies in the frontline, it basically lower the Russian warfighting capability by taking their supply out. This is harder task, may not be as useful (because there will be multiple supply dump serving the same area and you need to hit them all) but this will stop the immediate flow of supply.
As for why the Ukrainian do what they did, my educated guess is that they dont have enough HIMARS or M270s to make a large scale interruption that would work in Kupiansk. Which is why they are doing these hit and run type tactics.
The Russian is in strategic pause at the moment, which mean they are regrouping, and intelligence estimate they are probably 40-50% understrength, and in military term, they are culminated, unless the Russian can raise another 30-40 Full size BTG, they probably aren't going to move anywhere inland. Even after R&R, what I heard is they manage to raise 10 BTG of "volunteer" This is not going to be enough for the push.
So what the Ukrainian now doing is, they got their men trained in Ukraine, UK, Germany, Norway, France and Poland, they are raising 100,000 men every 2 to 3 months, what the Ukrainian is waiting on is the latest round of Western Equipment, afterward you can probably see the Ukrainian are going to make a push late August to early September, for now, Ukraine did the sensible thing and disrupting Russian supply as they waited.
That place has been contented more times then my mother jewellery in the will after she passed away.
Russia lost that place, they are staring down the Ukrainian counter attack. Ukraine lost that place, they can't do much but counter attack from the coast line.
And last I check, it was Ukrainian who held that place....
