It took two months in order to force the separatists to give up Severdonetska. It should be no surprise that Severdonetsk is still being held by those with orders yo not surrender while the soldiers die with their families. Severdonetsk is also a key
region which the Russians are determined to regain for Donetsk.
Once Donetsk and Luhansk secured, I expect Russian forces to dominate the East side of the Dnieper River.
Kiev and Dnipro will be the river crossing points, but the bridges may as well be non-existent.
It is easy to imagine that the river will be the boundary between Russia and US friendly Western Ukraine.
What of those regions between the Dnieper and Crimea, Donetsk and Luhansk?
We can se these regions as a DMZ, but that approach has issues.

It would have been better if this conflict never started with Ukraine willingly retreating its army while we find out who actually does live there. What of those regions 50/50 Ukrainian/Russian.
Most Ukrainians were not around in 1962, so they do not understand how the Cuban missile crisis was resolved? The Ukrainian situation is similar. Russia does not want nuclear weapons based in the Ukraine, which means no NATO.
NATO bases are the support bases for US nuclear weapons capable forces
The immediate targets are Mariupol and Severdonetsk city.
Zelesky will order Severdonetsk to defend to the last man while their families do not flee. Invariably, this would cost lives of women and children as they suffer the horror of a wartime siege.
We see the separatists at least had the good sense to retreat and to not make a suicidal stand while being overwhelmed.
Humanitarian corridors back to the West for future POW's would not be expected. Not all evacuees would be headed to Siberia; only those still glorifying Zelensky. Neurtal evacuees would be encouraged to return home once the smoke clears,
China would help Russia rebuild the damaged city infrastructure. The bankrupt West will help rebuild damaged infrastructure in Western Ukraine just as well as US rebuilds its own cities. Detroit is a good example. 'US will be asked to absorb probably 2
million refugees and US social security will foot the 40 billion plus per year bill
Uncle Joe will sanction Russian parliament, kick Russia out of the G20 while "promising" to absorb a large, unspecified number of refugees. A conservative estimate would place the number in excess of 2 million.
US can pay for arming with weapons while also paying to absorb the refugees. Just a prediction. It is not what I would will, as if my willpower is a control factor. It is not.

Battles of Severodonetsk was a series of battles between Ukrainian troops and Luhansk People's Republic formations during armed conflict in eastern Ukraine in cities and around cities Lisichansk agglomeration (Rubezhnoye, Lisichansk, Severodonetsk) for
control over these cities (there were no battles in Severodonetsk itself).

Timeline
On 22 May 2014 a convoy from the 30th Mechanized Brigade of the Armed Forces of Ukraine entered the city of Rubezhnoye. After that, she turned towards Lysychanska and Severodonetska. Along the way, the convoy was fired upon with grenade launchers and
small arms by LPR separatists from the detachment Pavel Dryomov. During the battle, Ukrainian Armed Forces lost two infantry fighting vehicles and a cargo Ural with an anti-aircraft gun in the back.[citation needed]

At the end of May 2014, there was heavy fighting between LPR separatists and units of the National Guard of Ukraine. The media reported on the use by the Ukrainian army of mortars, howitzers, Tulpan self-propelled mortars and Grad multiple launch rocket
systems.

On 22 July 2014 the LPR separatists retreated from Severodonetsk. Units of the National Guard of Ukraine entered the city.

As of 23 July 2014, the Armed Forces of Ukraine and the National Guard of Ukraine continued to engage in street fighting with the separatists. According to the fighters of the National Guard, they found one howitzer, more than 50 kilograms of plastids,
15 high-explosive shells and other ammunition in the city.[3] The fighting continued until 24 July, when in the city of Lisichansk, a Colonel of the NSU Radievsky, who was posthumously awarded the rank of Major General, was killed by separatists

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