Uh, then why cant Russia overfly Ukrainian airspace?
Why cant Russia interdict Ukrainian logistics?
Why is this war still going on? If Russia had such access to Ukrainian airspace there would be no supplies reaching the Ukrainian armies.
And, on your other points, why is it that Ukraine HAS taken back territory?
Your worldview seems severely out of whack.
Huh? They consistently do so. Have you missed the bi-weekly bombings of Ukraine's infrastructure? You can't do that unless you own the airspace.
The Russians can and DO hit any target they want to. Ukraine's air defense isn't sufficient to stop the missiles or drones coming in.
Because the goal of the Russian military is to destroy the Ukrainian military. And, that is happening in the meat grinder in Donbass.
The slow grind minimizes Russian causalities and maximizes Ukrainian losses. And, Russians have been aided in all this by NATO and Zelenksy both of which have insisted on using Ukrainian troops as cannon fodder.
Plus, the slow grind allows the Russians to keep churning out missiles, ammo and weapons all while Ukraine and NATO are running out of all that.
There is absolutely NO doubt about that. The only question is, how many more Ukrainians must die and much more territory will Ukraine lose before it is forced to surrender.