If you have your expected json result, you can just use library LateApexEarlySpeed.Xunit.Assertion.Json to do "json-level" assertion (yes, it considers "varying data structure of the JSON")

JsonAssertion.Equivalent("""
                {
                  "a": 1,
                  "b": 2
                }
                """,
                """
                {
                  "b": 2,
                  "a": 1
                }
                """);

(I am author of this library)