I swear Russia shills really thinks this like EU 4 or Hearts of Iron. Hurr Durr, my division just entered this province/city unopposed. That means it's mine guys. Change the color on the map!
That is not how this works. Isolating enemy strong points may have worked with Island Hopping in the Pacific war, but it does not work in a pure land war. Soldiers need to eat. Their equipment needs fuel. They need ammunition. You can't just leave entire brigades of enemy soldiers behind your line of advance because it's too hard to get them out. Those troops don't just stay in place. They can attack your supply lines. Cut you off, and then what? You are alone in the wheat field and it does not matter if the map says you own that particular region if farmer Stanislav and his buddies are shooting at you