They won't publicly announce the pullout till they are already out..don't give the Russians a chance to take a offensive.
From what I've seen they've fallen back across the Bakmut river and blown the bridge, so the Ukrainians have a better defensive position on that front at least, and might be able to shift forces to the flanks. to keep the road open or retake ground, or at minimum allow a more clean withdrawal if forced. River crossings have not been kinda to Russia in this war.Yup, whether they are planning a withdrawal or counter-attack on one or both flanks and when, it's in their interest to not reveal that until the other side finds out on their own.
Also, consider that if they pull out from Bakmut, that put's two more major cities, with much larger pop's than Bakmut had to start, in light arty range, and two more that will have to be rebuilt because Russia will level cities in order to 'take' them.
That means even if The Ukrainians hold there before being able to retake the Donbass, after Crimea, that is two more major cities Ukraine will probably have to rebuild a significant percentage of and evacuate civies/support personnel from. Also, lot's more roads in and out of those towns to defend.
Finally, any troops Russia isn't sending to Bakmut can go elsewhere, and Crimea, not the Donbass, is the decisive terrain.