Did Ambedkar oppose India's freedom struggle?
He wanted independence and said so; what he opposed was a particular movement's terms, not the goal. His disagreement with the Congress leadership was over sequence and safeguards. He held that freedom which left the internal order of caste untouched would free the country from foreign rulers only to hand it to a domestic upper caste, and that the Depressed Classes needed guarantees written into the settlement before, not after, power changed hands.
This made him a hard negotiator rather than an enemy of independence. At the Round Table Conferences he argued the case for his community directly to the British — which his opponents read as collaboration and he read as bargaining from the only leverage he had. When the Congress launched the Quit India movement in 1942 he stayed out and remained in the Viceroy's Executive Council, where he used the labour portfolio to push reforms he could actually deliver. Whether that was principled realism or a wrong turn is genuinely argued both ways.
What is not in dispute is where he ended up. When independence came he did not stand aside from the new state; he built its constitutional core and served in its first government. A man opposed to Indian freedom does not spend the first years of it writing the free country's law.