If Clausewitz is to be believed, killing the enemy army is priority 1, and territory only matters in pursuit of that goal.
Makes sense - if all combatants in the Russian army are dead, there’s no further need to defend territory for Ukraine. A boom with a border guard stamping passports would suffice.
Political goals are always the first priority. Fighting may be exciting, but it may also be irrelevant in the grand scheme of things. Defeating the enemy is neither necessary nor sufficient for winning the war.
When it gets to that point, the russian army without supply lines will have no other means to stay engaged.
Thus the priority from the very beginning was to disrupt the supply lines and ability to generate resources, meanwhile securing own supply and resources.
Ukraine needs more supply of long range artillery and lot more ammo for it ... yesterday and right now!
Makes sense - if all combatants in the Russian army are dead, there’s no further need to defend territory for Ukraine. A boom with a border guard stamping passports would suffice.