I find just so crazy how Mr Putin just prefers to fuck over Rusia and Ukraine’s future forever, than to just stop this nonsense war.

The predominant explanation is that nationalist or imperialist ideology drives Putin.

The other explanation, the reasons given by Russia for the invasion are that it's a preemptive war to protect their national security - and for those reasons they continue the war. See this case study for some quotes by Avril Haines, the U.S. director of National Intelligence and Jens Stoltenberg, the secretary general of NATO agreeing with this.

I believe both can be true.