The difference between this incident and something like Nordstream, is that sabotaging Nordstream had clear benefits for Ukraine. It hurt Russia financially, and forced the West's hand in looking for an alternative to Russian gas.

There's no Ukrainian benefit to sabotaging this dam. They don't need the propaganda push, they have the narrative already. And this is not on the scale of playing the blame game with missles landing in Poland, it doesn't make sense for Ukraine to displace thousands of civilians for optics.

Plus this would mean a pretty complicated mission in a Russian controlled area. This would have been much more involved than putting a bunch of explosives on a truck crossing the bridge from Crimea -which again, was strategically valuable for Ukraine to do.