Aspartame has been tested by far more than just the FDA and WHO, and nobody has ever found any link to any illness in humans, not ever.
And if you have any, you’d be the first.
It’s a straw man to argue your “uncomfortableness” with regulatory agencies as a reason not to trust aspartame. In fact, quite the opposite, as it’s the WHO who is doing the fearmongering.
And comparing it to any other approval processes is just a false equivalence.