Autism-related sensory issues are never going to subside. However, since my diagnosis and further research into the topic, I do find that when my brain becomes exhausted, my sensory issues are amplified. In my experience, mental exhaustion is a symptom of a problem, or a list of problems, in which we often do have some control over. Such as:
1. Getting on an "anti-inflammatory" or "autism" diet plan. Basically, it comes down to avoiding junk foods and carbohydrates, as these foods typically create an inflammatory state in the body,...including our brains. Furthermore, if you have the money, you can be tested for specific foods that you are sensitive to. There are companies on-line that will send you a kit to send a sample back to them and will give you quite a detailed list of foods that you may and may not be sensitive to. You may find yourself sensitive to foods you actually like, but are a source of problems for you.
2. Using a broad-spectrum probiotic. The higher the numbers of bacteria varieties, often the better. The gut-brain axis is a source of neurotransmitters for our brains. If you are on a limited diet, you could be limiting the varieties of bacteria, creating some degree of neurotransmitter imbalance.
3. Sleep! Melatonin and L-theanine are my "go to" helpers with this. Chelated magnesium helps the muscles and blood vessels relax.
4. Anti-oxidant supplements. Specifically, the ones I recommend have been studied in autistics and cross the blood-brain barrier. N-acetyl cysteine, resveratrol, and ubiquinol. Neurotransmitter imbalances in the autistic brain can cause inflammation, cerebral edema, and cell death,...but also intensify our sensory and communication experience.
5. Natural light and exercise,...a little bit goes a long way. Get outside in the sunshine, get some fresh air, and go for a walk. You don't have to go to the gym.
The bottom line, just like anyone else with a "condition" affecting an organ in the body,...the heart, the kidneys, the pancreas, the liver,...we, as autistics, have to take special care of our brains.
I think you were, perhaps, looking for a more psychological answer to this, but symptomatology is almost always secondary to some physiological condition. Treat the problem, not the symptom. Having said that, I will repeat,...autism sensory issues never go away completely, but it is more a matter of "management" and "minimization".