Hi Busterbill and welcome
T2 here, might still be relevant. I had existing tinnitus from the 1970s thanks to too many repeated loud noises, but it definitely worsened after my BG went out of range around 2010 or so. I had to have tinnitus-suppressing hearing aids around 2015, which helped to lower the tinnitus a bit.
Finally diagnosed in 2019, and BG in normal range from 2020 onwards. A lot of the tinnitus has since gone, particularly on my right side where sometimes there's nothing. Left side has improved but was always much worse and is still fairly constant. I can manage these days without the aids most of the time.
Can't be 100% certain it was the high BGs that made the tinnitus worse and that normal BG has made things a bit better, but that's how it went.