The currently most viable counter to artillery in Ukraine today appears to be either fpv drones, which have relatively short range and limited payloads, or counter-battery radar + artillery, which exposes your artillery by putting it in range of enemy artillery.

Ukraine typically has more accurate artillery than Russia, and seems to win more artillery duels, but of course still has an issue because of Russias huge volume of guns.

Targeting the drone operators is definitely something both sides do- they were considered priority targets last time I heard someone mention it. The issue, as someone else pointed out, is locating and hitting a small, highly mobile person or group that can operate from behind cover and concealment. That turns out to be pretty hard. Just consider that an infantryman’s primary survival strategy is “stay hidden when you can, covered when you can, and move as fast as possible when exposed”, and that drone operators are doing exactly that, while also not needing to stick their head out to be effective.