https://www.businessinsider.com/us-himars-completely-ineffective-against-russian-jamming-report-2024-5
Jamming is a very inexpensive tactic as the software is relatively cheap and it can take out munitions worth tens of thousands of dollars, Defense One reported.
Except some of them can -- some of the US shells use GPS and whatnot to help guide it to the target.
But also the latest "aid package" to Ukraine gave them less than a full day's worth of artillery shells. The US is getting fully tapped out.