Ukraine has concretely demonstrated their ability to perform deep missile/drone strikes (on the order of ~1500km) onto Russian strategic and economic assets.
Ukrainian drone capabilities in the near battlefield (up to ~20-30km deep) are also not contested. Russian milbloggers will openly talk about the difficulty of massing and movement in that area due to the saturation of drone coverage (and btw, this challenge is more or less symmetric).
So the article is not likely exaggerating any of their capabilities. However, it is exaggerating via omission.
In terms of deep strikes, the question is what the success rate of these missions are, what cadence can they sustain, what's the constellation of Russian lapses that have to line up for a successful strike, etc.
Another known area of weakness (that the Ukrianians are working hard on) is the middle range. How to strike quickly at targets of opportunity in the 50-500km range field. This was/is a capability that things like GMLRS and ATACMS provided, but I imagine the Ukraine is forced to ration those munitions carefully.
