Pretty hard, I think. The Prowlers have been mothballed for a while, and I'm sure that the equipment for the F-18 Growlers isn't fully compatible, so re-equiping them would be an effort. Then you have to train up pilots and electronic warfare officers on equipment that is very, very different from anything they have ever seen. Finally, the Iron Hand/Wild Weasel electronic warfare mission is one of the most difficult missions to train for and execute successfully. Once Russia is pushed out, I'm sure that it's a mission that the Ukrainian Air Force takes on, but I don't think they have the time or personnel to do it now. More's the pity.
That's not to say that they can't get an advantage locally with what they have that would allow close air support for ground operations in limited areas. That could be a game changer, executed judiciously and strategically.