Moon of Alabama makes a much more pertinent point, that the Ukrainian strategy of wrangling up every breathing male and throwing them into the trenches in the east, which the Russians are out gunning by orders of magnitude, will devastate Ukraine in the long run.

So there isn't much reason for the Russians to move, until Ukrainian society breaks, or rebels.

https://www.moonofalabama.org/2022/05/ukraines-forces-are-told-to-hold-the-line-where-russian-artillery-is-pulverizing-them.html#more