(amateur)
Qu: Why is it "combined"?
Ans: Because every aspect of successful endeavor requires combinations of machinery acting in perfect symphony. The example you are seeing now, one side getting blasted by materially efficient artillery in combination with UAV spotting. The defending side has not mastered the necessary component of counter-UAV operations, among many other necessary but not sufficient components. Success only comes with extraordinary combinatorics, most of the components of which are logically necessary to survival. One mistake... too many.
Qu: Thoughts on the Ukrainian operation?
Ans: I'm humbled of course, on so many levels. Technically, it's bemusing to be reminded of artillery's continuing pre-eminence for efficiency in fires, where salvo intensity and surprise isn't paramount. In the last few months I'd been listening to Audible audiobook "The Russian Way of War" and was impressed and grateful for the updated intuition regarding land warfare as largely founded on indirect-fire support of artillery.
I've been surprised by the continuance of Ukrainian aviation. However, this is a very, minor key with extended counterpoint operation -- put another way, Russians seem like the cat slowly disemboweling the mouse, learning anatomy as he goes, throwing the thing against the wall and checking various rebounding tactics, trying to get it to run some more... Where the cat learns of the mouse, Russian staff similarly learns about themselves, and about NATO. Presumably the aircraft have been successfully concealed and dispersed for rough-field operations, and/or airbases are operable and unmolested. Enumerating possibilities isn't speculation I guess...
Master class is an understatement. Limited, hybrid, this or that generation, I get confused. Of course we don't need to actually see the main event, whereas this is necessarily the intellectual focus of any serious man of war on the planet, observing and learning.