They also have a large and profitable industry selling state of the art tools to authoritarian regimes/dictators to target democracy activists and journalists.
But would they sell to Russia/China which is in opposition to their biggest sponsor - the USA? The answer is obviously: if they can get away with it. Personally it seems more likely to be US but that's just a gut feeling.
Perhaps not enough. I've certainly heard of shady companies, but I simply am not aware of a direct analogue to NSO Group. I am curious if you know of one!