Russia won't totally encircle IMO. They don't want to have to manage the imprisonment of 10,000 POWs.
What Russia has done in other regions is take control of the supply route via fire control and recon, denying AFU reinforcements and arms, whilst giving Ukrainian troops a high-attrition corridor to evacuate through.
That way, Russian troops don't need to take a bunch of prisoners but also don't enjoy superior numbers and supplies to any Ukrainian forces remaining in the pocket.
Against a larger enemy, one that poses an existential threat to Moscow, encirclement is worth the costs implied, just to disarm as many men in one operation as possible. But the general staff are likely very aware that it is "cheaper" to grind them down with pincer movement after pincer movement until the war is over.