Putin cannot afford peace because the Russia is too corrupt for prosperity to develop.
This, what you said here was the key threat to Russia if Ukraine were to join NATO and the EU.
Why? Because both organizations have benchmarks for democratic institutions and for a general intolerance of Soviet-style corruption.
Look at the former Eastern Bloc slave states that have joined NATO and the EU. All of them cast off their corrupt Soviet-era institutions and all of them are prospering with economic systems that don't reward hand-picked oligarchs by stealing from common people.
The spectre of a prosperous Ukraine on Russia's border is a threat to Putin. His greatest fear is when the common Russian people see the relative wealth of even
wartime Ukraine and instead of wanting to steal it they ask, "Why don't we have this anyway?"
Putin's greatest fear is what Russian dictators have always feared: Liberty and prosperity.