Just updating my original post. The tremors I was having have subsided and I'm now thinking they were most likely due to the onset of menopause, combined with some pretty severe insomnia being caused by some combination of menopause and anxiety. (Tremors, muscle twitching and insomnia are lesser-known symptoms of menopause, and can also be symptoms of anxiety.)

I've also been experiencing some left arm and hand weakness, pain, numbness and tingling for about 14 months that has not worsened. Sometimes a nerve pain runs down my inner arm and into my hand, thenar side (thumb and first finger most affected). Sometimes I also get numbness and tingling in my left leg and foot, that comes and goes.

Brain MRI came back normal. Cervical spine has some disc degeneration and disc bulges. There's something showing up on left brachial plexus MRIs that is most likely a benign tumor or cyst. Neurologist doesn't seem concerned, as we're not meeting again to discuss it until mid-February 2023, but she did say it could be causing or contributing to these symptoms. In the meantime I went to a chiropractor who immediately did x-rays and confirmed my c-spine and thoracic spine have lost all curvature. So now I'm working in an intensive program to help restore the curve in my c-spine and t-spine. It helps my symptoms so I'm feeling hopeful.
I want to note that the neurologists I've seen don't think that my straight spine syndrome has anything to do with my symptoms of paresthesia which seems bizarre to me. My lower spine has not been scanned as of yet. I'm going to continue with the chiropractic care and home exercises despite the neurologists not thinking it matters or that it will help. It has already helped.