Look up nerve flossing exercises on YouTube. Routinely doing these had the largest impact for me. You'll feel the ones that work on whatever nerve is inflamed.
Try to improve your posture. My general mantra is "lift your head as much as possible. Pull your shoulders back". It gets easier eventually. If your head lies forward from the spine you have a hunch. You may notice a small lump of muscle behind your neck. That's bad. There are exercises to try and strengthen the opposite muscles.
If you sleep on your arms try to stop as well. I recommend sleeping on your back. Fluffy couches and back rests sacrifice posture. Don't use a laptop in bed.
Sleep, eat nutrient-dense foods, and run or swim. Avoid alcohol. If you do pushups or bench press, make sure to exercise your upper back equally to avoid imbalance.
It is frustrating that there seems to be only trial and error in all of this.
But then, after having seen doctors and neurologists, and finally a physical therapist, I came across my salvation: - Exercising my hands.
I very rarely see this mentioned for some reason. I exercised regularly, but only the bigger muscle groups, rarely grip strength and wrist strength. It felt counter-intuitive to exercise my already extremely painfully aching hands (when typing), but using grip weights and other methods to work out my hands and wrists, the pain went away quickly! If you are not diagnosed with carpal tunnel, and not already doing this, definitely try it, it saved my career.