Up until June 1941, during the days of the “blitz”, Britain was alone. That is what Churchill was recalling, in 1945.
And the proper quibble in this is not about the USSR being involved later, but about the British Commonwealth and Empire (India, Canada, Australia, etc.) and the US, which was being extremely helpful.
I left behind, in the US, nearly all of my library, about 1000 volumes of which were on WW2 alone. I still have some books, among them many of the works of David Glantz.
What if we supplied Ukraine with fuel air explosive bombs, thermobaric bombs and the drones to deliver them and the capability to hit Russian civilians deeper inside Russia with them? Bring the terror and suffering directly to Russian civilians in cities in Russia?