Putin is not daft (but not a genius) but is callous and also fairly nasty with very nasty friends, this is what makes him the more difficult combination and the spineless west find it easier to pretend he isn’t a problem so they don’t have to deal with it
if you want a really good explanation, read Winter is Coming by Garry Kasparov, has useful pointers on what to do with him, a book that Kasparov laments (on twitter) that should be out of date by now but isn’t
trump is a moron, end of. So is KJ Un
if we dealt with Putin (see above book for how) then KJU would be less of a problem because Putin trades with NK, and it would force China to wind in their aggressive behaviour because they’ve seen it happen to their next door neighbour