1) Do you hear it away from your home? If yes then it’s in your ear not your router.

2) The only solution to tinnitus is to stop fixating on it and eventually stop thinking about it completely. The only way to do that is to make sure you can never hear it. Learn how to mask yours with music or white noise. Especially while sleeping. It will eventually calm and might even go away. 3) Do not seek tinnitus support groups/subreddits online. They are fully fixated by definition and just reading their posts will make your symptoms worse.

1) Yes, I do hear it away from home. I was thinking of it could be triggered by coil whine / high frequency noises like the router produces, then stays for some time and then gets re-triggered by the next coil whine.