This scenario is the status quo ante. On the ground, it looks a lot like Scenario 2, but it means Russia gained absolutely nothing from the war. As a result, it would be much more difficult to sell to the Russian people than Scenario 2, which can be spun as a victory of sorts.
Putin won’t sign anything giving Scenario 3 any kind of permanent status. It would be more of a pause than a Korea-style armistice. Would he survive the failure at home? Probably, because it wasn’t an outright defeat, but the natives would start getting restless.