It could be an IQ thing. Or it may be that military history is a hobby. I have @1000 volumes of it currently on my shelves or my tablet.
It is quite common to fight for a couple of months on a line, and the it breaks open. Or a change in tactics permits a more effective gnawing thrpugh a defensive system.
As for casualties, make no assumtions, there is no trustworthy information on either sides losses.
Well ok, vehicle losses are much more trustworthy as there is video. Count those numbers if you like. But cumulative photo/video evidence is not on the Russian side. And vehicle losses on either side do not indicate human losses on the scale either side is claiming.
Actually most troop carriers and Bradleys are usually full of troops when they are moving, so that would be a part of the. troop casualties. Also the Crimea Bridge is overated as barges and Ferries were used for 100 years between the land, and still is. So even if they cut off the land route, which is doubtful at the rate of advancement, they will Never get Crimea. At best, they may get nuked.