Why is Putin fighting like it’s 1939?

One hyphotesis is that this would be the only predicted way - BigData, AI? - to wage a war like this and not endind into an unexpected nuclear interchange with NATO.

Everything else, including several parallel / russian doll style maskirovkas - losing hundreds of tanks because the lack of heavy use of its air forces, momentarily detaining fully predictable corrupt high level staff here and there, throwing money here and there to be stolen by the same corrupt people - would be just to hide the conscius decision process even from his own people, and also, intended.

So a war like this could actually be the lowest cost conflict feasible to achieve the desired outcome, if you want to start rebuilding the Iron Curtain given the current state of affairs (technology, politics, social stuff).

That, or Putin has lost it. But it still looks like he has not.

Putin's Russia is more dysfunctional than Soviet Union ever was. Russia is solely hydrocarbon based economy. It has military for a typical hydrocarbon based dictatorship.

Regular competent military career officer is a threat to internal security. Top ranks in Russian military are filled with generals with career in internal security (FSB and similar). They are competent in internal security and small "special operations". They don't know how to plan and execute complex military operations. They just yell and punish when things don't go as they planned.