Russia’s apparent resilience is being kept up by policy tricks and cash

Most of the military analysts I have read have essentially dismissed the idea that Russia was planning to use nuclear weapons--there's been no force posture changes that would precede imminent use of nukes. The worry instead tends to come from pundits and politicians, and are probably driven more by a desire to support (or not) Ukraine.

The biggest concern is that Russia has consistently threatened nuclear responses to military incursions of its territory (which is not unusual, all nuclear states do this), but the territory that is included in this nuclear threshold is... unclear. Russia annexed Crimea in 2014, and Kherson, Zaporizhzhia, Donetsk, and Luhansk in September, but essentially nobody recognizes those annexations. Immediately after the annexation, Putin did another round of reiterating nuclear threats. Note that Russia did not control much of Zaporizhzhia (including its largest city and administrative center), and Russia lost control of much of Kherson last month--if you took Russia's claims extremely literally, Ukraine was already in a position to trigger nuclear threshold response.

Realistically, no one believes that Putin will use nukes in response to military failure in Ukrainian territory, with the possible exception of Crimea. The annexation may have been intended to try to extend the strategic ambiguity of nuclear response that exists right now for Crimea to the rest of Russian-controlled Ukraine, but it probably had the opposite effect (which is to say, people find nuclear response to a Crimean incursion less likely as a result of the annexation). My sense is that a lot of these messages are directed towards trying to get the West to force Ukraine to the negotiating table and ratify the status quo in lieu of being able to achieve military victory.

Your argument would be valid, if this was something exclusive to Russia, and not a common mutual thing between Russia and NATO. NATO bombers just as well fly into Russian airspace, NATO deploys military manoeuvres at Russian borders, and NATO states politicians are just as keen to ramble about nukes as anyone else.

If Russia is bombing civils then we must end the war asap

The fact that we don't and let it linger means other interests prevail

My sourced comment got flagged, that's quite telling

That's part of why WWI was so hellishly destructive for Europe - national leaders, military planners, educated elites, etc. really didn't get that modern(-ish) industrialized warfare was profoundly different from "the good old days", and they made endless bad decisions based on obsolete "wisdom".

My understanding of Russian politics is that it is primarily driven by apathy: the population will support what the government does, so long as it doesn't affect them. Russian mobilization is a violation of that tacit agreement, which is why it seems that mobilization is being targeted more at marginal groups with less political voice (e.g., ethnic minorities).