A
I was envisioning something after the WarPac/non-warpac boundaries have solidified but at a point when there's still a little wiggle room for the US to change its mind about supporting colonial empires, but I would pay US dollars to read your scenario.
Assuming anything even vaguely resembling OTL WW2, if the Americans decide they would like an end to colonialism more than they fear Soviet Europe, the empires end very very quickly. Probably with a Soviet-backed coup in Paris for starters, and with all parties in London scrambling to work out how they can show more commitment to decolonisation and hang the casualties in the process.
I was envisioning something after the WarPac/non-warpac boundaries have solidified but at a point when there's still a little wiggle room for the US to change its mind about supporting colonial empires, but I would pay US dollars to read your scenario.