is sleep-maintenance insomnia more likely to be caused by a mental issue or a physical issue (eg. hyperthyroidism)?

Question

I have some symptoms consistent with hyperthyrodism.  I am super anxious and edgy all the time and I suffer from extreme insomnia.  I have only gotten about 4 hrs. of sleep on average since mid-March.  I used to think it was due to Covid-19 anxiety, but looking back I started having sleeping problems back in December of 2019.  My biggest issue is sleep maintenance.  It started with me waking up early in the morning (7-8 AM) and got progressively worse.  Right now, I always wake up about 2-4 hours after falling asleep in a super agitated/edgy state and I can't get back to sleep no matter how hard I try.  Furthermore, I don't feel tired (sleepy) like you would expect.  I just feel physically and mentally fatigued beyond words.  It's like my need for sleep has been reduced.  It's sort of like I'm experiencing a drawn-out episode of dysphoric mania.  Besides this, I am not really experiencing other obvious symptoms.  Mentally I seem to be fine.  My BP is normal.  My heart-rate is normal.  I have not lost weight.  Could it be thyroid issues?