Nazis got unexpected help from USA and UK?
Nope, I do recall the UK supporting Ukraine in whatever Ukraine would decide. The UK cannot force Ukraine into a war simply because there is not leverage to do so even in the case that this would be in UKs interest.
Ukraine is not fighting anything like a "desperate war to the last Ukrainian", they are fighting a war that is clearly possible to win to the point in which Ruzzia will think twice before trying another land-grabbing in a few years. Next time, whoever is in power will know what is the cost of attacking the neighbour and very particularly, how trustable are their sources of information when they told the old Putler dude that Ukraine would not resist and that Europe would not respond (that was an epic blunder).
Of course it's not a "desperate war to the last Ukrainian." They're volunteering for the benefit of the necessity of depopulation, because out of love they know that the whole world is suffering from over-population. Lol.
I don't think that Biden will be able to force a draft on Americans. And the Nato countries don't like the idea at all. This means that outside of a few strays that go to fight for Ukraine, all Russia has to do is keep on killing Ukraine soldiers. The problem for Russia is, when all the Ukrainians are dead, there won't be anybody left to surrender.
Consider Dresden in Germany in WW2. They thought they were safe, being rather far from Berlin, and near the Czechoslovakian border. But they got bombed right off the map, and now Czechoslovakia is even gone.