If that's what he thinks he should follow his own aggressive logic. The more powerful countries will win. He thought he could invade Ukraine without a direct fight. But he got more than he expected. He should have withdrawn in a month and threatened to do so again. That he didn't suggests to me it's more than what you posit.

Every day he wastes people and material on the war will add to Russia's military weakness in the future. He keeps fighting because, as many have pointed out, it's more rational to do so because he might get lucky and quitting now would start a final accounting of the real loss. He would look weak and would eventually be deposed.

The U.S. has not attacked Russia. Indeed, it has stood by why he took parts of Chechnya, Syria, Georgia and Ukraine. Many say, that fault is there. That the error in your thinking is you think this all began with Ukraine. That you don't recognize that de-escalation in the past has only lead to more power grabs in the region.