We cannot be sure if this is accurate, but the writer seems to know what he’s talking about:
“There is hard fight to come in the Donbas, where Russia has the advantage of defensive positions, but Ukraine has far better weapons, intelligence, resupply, and motivation. The looming question is how long Russia can stay in this fight as its army continues to lose vast numbers of men and material and its economy struggles — and fails — to replace them. Meanwhile, NATO’s powerful, long-range weapons are now reaching the frontlines. Those weapons, combined with good intelligence and precision targeting, should shift the advantage to Ukraine, whose outnumbered forces are determined to win back their country.”
I don’t think Putin will accept defeat.