Lessons learned first six weeks of war

What can we learn from the first six weeks into the Russian invasion of Ukraine?

In the weeks and months leading up to the invasion of Ukraine, Russian President Putin repeatedly rejected accusations that he was planning to start a war.  Putin lied, and he is most likely lying again about his army’s next moves. That is the message from NATO Secretary-General Jens Stoltenberg. If Russia has indeed underestimated Ukraine and overestimated its own capabilities, how long would Moscow need to reorganize its attack?

QUESTION: Why is the world tolerating this tyrant?  It is “most” of the world against Putin.  This could end fast if the right people would make the right decisions.  Societies around the world do not need this war and the world can’t afford a long drawn-out war.