You don't have to convince me of the dangers. I have written articles as well about the problem with escalation of the conflict with Russia:

https://erik-engheim.medium.com/you-misunderstand-the-threat-of-nuclear-war-with-russia-faa07972050d

However, that is a separate issue from the question of whether Russia sucks and conventional warfare or not. They do. They win through numbers and excess brutality. That is their usual game plan. Now they face an enemy with half decent weapons and training which isn't tiny. Russia has crushed countries with tiny populations before, but Ukraine is over 40 million people. The "quantity" strategy will not work as well this time.

I don't think the world comes to and end because Russia loses. They are not run by cartoon villains even if we like to think that. As long as Russia is not directly threatened by an invasion or nuclear attack they will not use nukes. We just got to make sure we don't do anything that kickstarts Russian paranoia and drive it to extremes.

As long as it is made very clear that the West is not entering the war, there is not reason this should escalate to nuclear war. If we institute a no-fly zone however we could get closer. We can probably give Ukraine planes but we can ourselves not be flying those planes.