There has been no appetite for such from those in power but would engaging Russia in Ukraine mean all out apocalypse or even much of an increased chance of such?

You would like to think the inevitable mutual destruction would ward off anything getting that far.

I'm thinking in terms of engaging Russia purely within Ukraine, things clearly become very different if Russia itself is under any threat. We are already sending weapons which are killing Russians, have trained soldiers who are now killing Russians and basically in an economic and cyber war with Russia.

Pretending we aren't in some form of conflict with Russia feels odd at this point. If Putin genuinely believed NATO might deploy troops to support Ukraine, I'd imagine he never would have invaded in the first place.

I'm assuming if Putin pulled his army out tomorrow, within a few months most of the International attention will have moved onto something else, leaving him to plot their next excursion.