I sort of think the Knanaya canonical situation and its friction with Kerala civil authority is a very good foil for contemplating the ambiguities and tensions in Dignitatis Humanae:

It seems true to me that the One, Holy, Catholic, and Apostolic Church in a very real sense contains many “religions” within her communion, and that the porous and ambiguous category of “religion” belongs as much to her catholicity as it does to her unity.