By now you must be aware that the "all powerful and glorious" RF Air Force is unable to do anything in Ukraine. Missiles are ok to destroy nurseries, commercial centres and the like but real military use requires precision not "precision". To put it plainly, the RF cannot raze anything to the ground. There was no option to "bomb" and instead the Junta took the non-decision of sequestering civilians and send them to die.
Bombing with high-explosive bombs was successfully used by Russia, in particular at Azovstal and near Kherson, where there is no threat to defeat civilians.
On regards to "synchronous"... funny that you mention that. The RF is absolutely unable to coordinate the deployment of 300k freshly recruited pretty much demotivated and unready poor bastards. Expect them to arrive late, unequipped, untrained, unmotivated, uncoordinated... This is the perfect recipe to destroy de population growth rate of the RF for the next 10 years.
Ukraine somehow coped with the task of mobilizing more than 800k civilians, Russia has a simpler task.
Yet here you are, still on phase 1 "denial".
I think you are too exalted by the local success of the Armed Forces of Ukraine near Kharkov. Ukraine still has no chance in confrontation with Russia.
Why did Putin not close the borders? Perhaps the damage would have been excessive or perhaps this is designed to send abroad anyone who might actually dissent with the Psychos Junta.
What for? Russia has a multiple greater mobilization resource than Ukraine, it's okay if some people go abroad, it's their choice.