If your armed forces collapse it doesn't cause WWIII. If your economy collapses it doesn't cause WWIII.Yes, that was the plan. But It is you who is in the corner now. You can't win in Ukraine without starting WW3.Russia invaded Ukraine because their economy is shit and having 40% of the world’s grain supply would help fix that.
Russia also invaded Ukraine because they thought it would be quick and easy.
I suspect they no longer think that; But it's too late now, they've painted themselves into a corner.
Nobody's going to invade Russia. There simply is no reason for WWIII.