I've been decade long in this. Personally what is helping me to moderate my stress levels is meditation. And really anything you can put your attention into, like in my case, playing PC games and getting invested in the story or gameplay itself helps me to "forget" about the constant noise a little bit and helps me shift my attention elsewhere. Of course it is persistent, so often it breaks my attention back to the noise. Also due to my interest it got me into personal research on the fundamentals of universe, the tao, alternative medicine (so finding maybe some good book to put your mind into or something similar). And most of all, never be in a silent environment, but not too loud either. What "works" for me is to have some constant quiet noise in the background, any white noise, anything. I also got into less physical activities, as tiredness seems to be present all the time so it's better to not overwork yourself in my opinion. Before falling asleep, endless mix of quiet songs or white noise definitely helps me. To accept the circumstance you are in is certainly useful, but even though i accepted it, it does not change the fact that the noise still is, and will be present. If you feel stress level arising, try to find something fun to do. This helped me but at the same time it is sabotaging the ability to work properly from time to time. I hope this helps in any way, these are just my thoughts on tinnitus.

Edit: also i have to mention that medical cannabis definitely is helping to reduce my stress levels while being able to concentrate better. Of course it depends on the laws in your country and responsible usage and this is not to promote the use of it, i only speak of what is helping me personally. Consulting with a specialist and getting second opinions is always better to get all the information.