Chug:
Hitler's main problem was his strategic decision making in 1941, when he helped Mussolini and attacked Russia within months of each other.
In my view he should have finished the Greek and Balkan campaigns off first, sat tight in the desert and up armed for a move into Russia in 1942 or even 1943. The Whermacht was still to a very great extent a horse drawn army. Time would have allowed his divisions to be mechanically re-equipped. The other factor was that he went too late in the year and did not plan or even contemplate a Russian winter.
But today, we now have Putin as you say nibbling away at the western states and Turkey is slowly becoming embroiled with border incursions from Syria. Remembering Turkey has invoked Article 4 of the NATO Treaty. None of the NATO forces have the resources to fight one war let alone two. We lack resources such as material and manpower and outright will to get involved in Eastern Europe. We also do not have across Europe the political 'balls' either. The last 35 years of downsizing and so called peace dividends could be just about to bite us very severely in the backside and there is SFA we can do about it.
Putin as you put it maybe a 'chancer' but he's a very astute chancer.