Concession acknowledges a point before countering it (Although X, Y). Contrast highlights a difference between two things (X whereas Y). C1 requires mastery of the grammar of each connector (clause vs noun phrase), register differences, and advanced forms: granted, admittedly, much as, for all, no matter how, that said.
Although/though/even though + clause. Despite/in spite of + noun/gerund. However/nevertheless/nonetheless + clause (with comma). Choose the grammatically correct form.