It's based on several flawed assumptions: that Putin's death will happen soon, that Putin's death will lead to a leader with a radically different and more amenable geopolitical vision.
Do understand that the popular narrative in Russia mirror's the ours exactly: "We can't just roll over and let the West have Ukraine".
I'm sorry, but "keep fighting until Putin has a heart attack" is stupid beyond belief. The only way to safely end this conflict is to freeze it. Continuation risks catastrophic escalation.