>>64264774 (OP)
Reasons why Ukro-Russian war devolved into trench warfare was because russian logistics were, and still are even more so, fucked so that they can't apply necessary pressure on the weak points, and their command structure is atrocious.
Whereas Ukraine simply had no ability to maneuver effectively until after a year or two, at which point russians had already had plenty of time to mine and fortify fuck out of everything, making mobile assaults costly and difficult.
Problems exacerbated by the fact that aerial superiority can't be gained due excessive amounts of Anti-Air both sides have.
So simply put, if you prepare for the sort of war they are having, you are preparing to lose slowly and costly way.