EM captured is proportional to area. An electric grid is big, so it’s easy to fry even from a distance. A drone isn’t really, so you need a ton of power, and:
with appropriate shielding on their own equipment
We’re talking about guys who don’t even use the armour they already have properly, remember. Custom EM shielding for their barely-refurbished 1960s radio or the civilian one they bought from more competent people in China is not really on the table.
Just more jamming is an option, but apparently they have trouble doing even that in a directed enough manner. Also, it’s pretty much certain Ukraine’s drones are getting more and more autonomous.