I had similar case recently, in C++. I ended up spending a few hours writing a simple JSON differ - a bit of code that would parse two strings into a DOM object graph using a rapidjson, and then walk down them simultaneously - basically, I implemented operator== which, instead of terminating early, recorded every mismatch.

Then, I packaged it into a Google Test matcher, and from now on, the problem you describe is gone. I write:

  EXPECT_THAT(someObject, IsEqAsJSON(someBlobFromADifferentFile));

and if it fails, I get output like this:

  Expected someObject to be structurally equivalent to someBlobFromADifferentFile; it is not;
   - #/object/key - missing in expected, found in actual
   - #/object/key2 - expected string, actual is integer
   - #/object/key3/array1 - array lengths differ; expected: 3, actual: 42
   - #/object/key4/array1/0/key3 - expected "foo" [string], actual "bar" [string]

Etc.

It was a rather simple exercise, and the payoff is immense. I think it's really important for programmers to learn to help themselves. If there's something that annoys you repeatedly, you owe it to yourself and others to fix it.