I had a somewhat sudden onset of tinnitus a few weeks ago. After reading that it can be caused by earwax or foreign objects, I bought an earwax camera and removal tool to take a look. I was able to remove a single fairly large piece of wax (5-6 mm with a flat shape) that was causing the issue. It can also be caused by hair or other stuff touching the eardrum. It’s a cheap and easy way to eliminate a foreign object as a tinnitus cause.
Taking a look with the camera can also give you a better idea if you have significant wax buildup that is best left to a professional to remove.