[mr_mitm]

The data we have about black holes is nothing more than evidence of objects with a size and density which are only consistent with black holes according to GR. Without assuming GR is true, you have only evidence of unusually dense objects, nothing more.

[uoaei]

The alignment of certain evidence of certain parts of GR does not necessarily imply the correctness of the parts of GR that are not relevant to the evidence we have access to.