The universe which presumably depends for it's existence on the laws of nature ...
Well actually laws of physics, but nonetheless, yup I agree.
but not vica versa
In other words the universe depends on the laws of physics - yup again I agree.
... is comprised of space time and matter/energy.
Which are themselves dependent on the laws of physics - space/time don't really exist outside the laws of physics in the same way are planetary orbits don't really exist outside of the laws of gravity (one of those fundamental laws of physics).
If the existence of the laws is not dependent on these for it's form then in what form does it exist?
You have already let slip a bit of a clue. The laws themselves cannot be measured directly.
They exist as a fundamental law of physics just as gravity does, or light or sound etc.
What manner then of natural thing cannot be measured directly?
Very few things are measured directly, or even experience directly - whether we measure temperature by the indirect change in resistance of a thermocouple, or detect light via chemical changes in the eye and neural transmission to the brain, these are indirect. But just because they are indirect doesn't mean they are inaccurate nor inconsistent, because the measurement systems are themselves based on fundamental physical phenomena and laws.
And if you can allow something which you cannot measure directly how can you then deny this property for, say, God?No see above. If you can readily allow The laws themselves not to have physical properties or be dependent on there existence then you have no warrant to deny that in other things.That is almost like saying 'God sits above his creation'...….but God is a spirit in heaven. Where and what are the laws then if not dependent on time, space, orbits of planets etc.etc?
Nope - because the difference is one of consistency and prediction.
So to take gravity as an example - I can use the fundamental laws of physics to predict the orbits of the planets. I can use (and people have) anomalies in planetary orbits to predict the presence of a more distant planet affecting gravity - and guess what, you find that planet. I can use those fundamental laws (and their indirect measurement) to design a rocket with its trajectory to leave earths orbit and be capture by the moon's orbit to allow astronauts to visit the moon.
Sure the measurement may be indirect, but the concepts and the laws can be verified through prediction and through the predictable function of engineering systems or identification of physical phenomena.
None of that can be attributed to a purported god - people have at times tried to base predictions, observations and outcomes on god, but guess what ... the earth is at the centre of the universe, the rocket crashes, the church congregation aren't protected by god's love from dying from COVID-19.
