The end game is that eventually everyone will get involved, and we will be posting HN comments from the trenches.
Most liberal democracies only exist today because of the sacrifice from those living in liberal democracies in the 1930s and 1940s. We cannot back down when it's our turn to protect fundamental values.
At this point, either Russia voluntarily stops it's invasion and leaves Ukraine or inevitably NATO will have to step in. Whether it's before or after Russia invaded a NATO member is still to be determined.
As Russia is all-in, the only option on the table that prevents NATO from stepping in is to support Ukraine and supply them with the necessary and sufficient equipment to drive out Russia. If there's no political consensus to deliver what's needed, it's only a matter of time before Europe's armies are deployed.