I think you people should simply understand the stakes of the upcoming battle. Let me visualize
Russia is sending 500k troops to fight when their estimated fatality count is only somewhere 180k after a year. Zelenksy thought it'd only be 300k, as he stated, but he estimated it to be that number now at the border. This illustrates how serious they are about this blitzkrieg. A few outcomes may happen
1) if Russia wins, we're all fucked.
2) if Russia loses, it will have no capacity to perform a major offensive in any foreseeable future. 500k dead, Ukraine gets better weapons and rebuilds itself. It also declares total victory pre-emptively. Russia will not, however, concede defeat, and this is where things will get ominous.
So yeah, that's why I consider what Russia is plotting to be their final outing and last major offensive. And in either scenario, it's going to be rough for the world