I saw several of your posts and want you to know I have the exact same sound / cause of this condition. Hang in there, as it will get better, even if simply due to getting used to the sound.
For me, significant triggers are red wine (and any alcohol), vitamin D3 and Niacin. I am deficient in vitamin D (found out through recent tests), and when I took the 1000 IU pill for vitamin D, my ears rang like never before. Red wine and alcohol are things I have enjoyed in the past, but I notice a significant increase in the dog whistle ringing when I drink, so I have backed off considerably. Now, things that help. Advil. I take two every morning and notice a considerable decrease after about an hour.
McKenzie Method neck exercise. YouTube it and do it. I have no idea why this works, but I do it five to ten times a day and have found relief. YouTube search "Vikas Agarwal tinnitus" and try it out for a few days. Don't give up on the first try!
Rain water sound. For whatever reason, the traditional sound machine white noise makes my tinnitus much worse, whereas the rain sound eliminates it completely. Must have something to do with the high frequency hearing loss, which three ENTs confirmed I now have in my right ear.
Now for the tough one, getting used to it. The high pitched sound is likely caused by the vaccine, which caused a neuroinflammatory response. I'll spare the details, but I've read for hours and hours on the cause of vaccine induced tinnitus, specifically related to COVID-19 and COVID-19 vaccines. Basically, the reaction of our body's to the vaccine was an excessive inflammation that actually damaged the hair follicles in your cochlea (inner ear). The brain then turns up the volume to try and hear high frequency, thus creating the feedback noise we hear. Much like hearing an AM radio station that doesn't come in well, so you turn up the volume to hear the words, but also hear that feedback increase as well.
The bottom line and reason for this post is that you can beat this and get back to a more normal life. I was very down in the early weeks (understatement), but have noticed the more I focus on what is working, the less I focus on having to deal with this long term. For sleep at night, which is the first thing you need to figure out, try the rain noise. I have increased the amount of water I drink each day by making sure I get 12-15 cups every day, which seems to also help. Try a few of these things out and let me know if you find anything improvement. Most of all, know that people like me are working through this with you, and stay strong!