Use: I'm sure they do just fine
Maintain: I doubt it too. Then again, I doubt US Army soldiers maintain them either. They probably get maintained by contractors.
Russian radar is amongst the best in the world for ground units, largely thanks to ukraine. They'll spot and take those out quickly I'd imagine.
So far they've posted fake photos of (not) HIMARS getting destroyed and assumed people are too dumb to notice the difference.
Logically we can safely assume that some of these will eventually get destroyed in war, but the fake propaganda and lying suggests that they cannot quickly and easily take these out, otherwise why not post the real thing? It would be terrific real PR. So in general let's go with the reality that we can verify rather than treat the pathological liars as competent and take their claims at face value.
Doesn't seem likely that Ukraines could use an maintain these things after a couple weeks training.