I think such a gamble would depend on several factors, all at this time unknown.

1. How quickly will the 300k reserves be ready for action and how well will they perform

2. Will defenses hold (or most of them mostly)

3. Will offenses near Bakhmut and/or Donetsk be successful or at least pin a large number of AFU

4. Most important, how successful will the continued missile attacks be on cutting logistics support from Poland

I would think (but I'm no military expert) that an attack on the start of the logistics line from Belarus to Lviv would be a good "bang for the buck" attack, if 1-3 are good and 4 is not. If all 4 are good, then I think Russia will continue grinding Ukraine down while pushing (3) - as that is their stated goal from the start.