It is very easy to end the conflict, it is just that the only realistic scenario for ending the conflict does not suit either Kyiv or Washington.
I think you're wrong, Putin's death suits Kyiv just fine. Not sure about Washington, he's been dead for a while so probably has no strong opinions about this.
I think your opinion is very infantile. It's like thinking that there would have been no World War II if Hitler hadn't failed the entrance exams to the Vienna Academy of Fine Arts (twice).