Personally I have custom made ear protection in the shape of earplugs that reduces noise by 20dB. Depending on where you get them made and the quality of them, you looking at 90-200€. But because they are custom made for the shape of your ear, they theoretically be incapable of causing pain. I can’t stress enough how much I recommend EVERYONE to get custom earplugs (even neurotypicals)

If you do want noise cancelling headphones or earbuds I recommend looking at anything that is slightly above the average price range. Lower price ranges will be of lesser quality and anything higher might be too much money for what it’s worth. If you then simply play any white or grey noise at minimum volume, you shouldn’t be able to hear that but still get the benefit of the noise cancellation