That's mostly a theoretic scenario imho:

Suppose there's a cease-fire, and Russia moves a mass of its troops near the Baltic states (to "poke" those, or worse).

What would stop Ukraine @ that point from grabbing the opportunity & regain Russia-occupied territory?

In short: those Russian troops aren't moving until there's a durable end to the war. Which Putin doesn't seem to want.

I suspect it's a matter of time before Russia's economy and/or its leadership cracks. At which point things will happen fast. And replacement Russian leadership probably won't have appetite to continue the war (or go dance with NATO).