You're clueless to what is going on and what the Russian strategy.
The Russian strategy is to force a surrender under their terms. They need to keep the government in tact to do that.
The Russians don't even necessarily want the whole country under their control, just the eastern half. The goal was to free Donbass from an eight-year war the neo-Nazi Azov bastards were determined to fight and get the water flow turned back onto Crimea.
Sure. That is why they sacrificed 200 elite paratroopers in a foiled attempt to take the airfield at Hostornel, and lost hundreds of armored vehicles and thousands of casualties near Kiev.
If they capture a a government, it is easy enough to force terms with that government.
It is practically SOP to do so.
Maybe that was the plan. If so, the Russians need better planners.
So, all this is about getting Zelinsky’s signature on a piece of paper? Brilliant! Why bother with regime change, and all the trouble of a puppet state, when you can have that sort of concrete guarantee for all the ages.