I'm coming around to the opinion that Ukraine does indeed have a real navy, but it's a cutting-edge 21st century navy that doesn't necessarily always look like a conventional 20th century navy.
I mean, Ukraine is probably never going to be very interested in buying expensive capital ships for long-range force projection outside the Black Sea. Their focus is always going to be coast guard, security of the trans-Bosporus trade route, and the implication of commerce raiding.
So at some point, we'll probably see them augment their fleet of boat-torpedoes with guided missile frigates. Probably some drone tenders and ELINT/EW boats. Maybe one or two aircraft-carrying cruisers.
But they're already working on their third generation of boat-torpedo. That's navy enough for me, at the moment.
ETA: And the best part of this attack, in my opinion? They hit a modern intelligence/electronic warfare ship. Of all the ships in Moscow's inventory, this is the one you'd expect to be able to detect and jam the drone control signals. And this is the one you'd expect to be doing exactly that, since it's in the Black Sea and Ukraine has made no secret of its boat-torpedoes. I'm not saying the Ivan Khurs had one job, I'm just saying...