but none of this explains how Russia would beat an adversary that has five times the military capacity.

Because I think your premise is bunk. But we'll see who's right in the event such a head-on confrontation comes to pass.

those countries would have to forego their trade relationships with NATO countries. Not going to happen

I don't agree that Russia would have to rely on other countries, and I certainly disagree that in the event it were necessary other countries would not come to their aid. Russia has more friends throughout the world than the West does, they are benefiting now from relationships established during the Soviet era throughout the global south. And in case you hadn't noticed, many countries in the "Rest of the World" are lining up to join BRICS; and while it's true all its members - including Russia and China - haven't closed the door on trading with the West, they are also setting up a system where they can engage in trade according to each member's own national interests without having to tolerate Western bullies telling them what they can and cannot do.

It makes no sense to escalate tensions. If Russia were to do that

They're not planning to, but they've said they will achieve the objectives they set out at the beginning of the war. They've also said they will not attack NATO countries UNLESS those countries attack them first. As for nukes, I think the greatest danger is from the US where you have utter morons talking about "limited nuclear war" being an option.

The non-Western world is watching what the West has tried to do to Russia because they realize it can and in some cases has already been done to them - the seizing of Russia's reserves, the attempt to destroy the Russian economy with sanctions, the 2014 coup that led to a civil war on its borders.

Sanctions are considered economic warfare and a violation of international law but as everyone knows, the West routinely violates international law in favor of the more pliable "rules-based order" - as one pundit put it, we make the rules, you follow our orders. So no, I don't think Russia will be isolated; I think they'd get lots of support if they ended up taking on the dreaded beast of Western hegemony. Actually, they've already done this by drawing and defending clear lines in the sand about their own survival and security interests.