I have read your post and wanted to share mine. I have Long Covid, no taste or smell since having Covid in December of 2022. I also suffer from Hashimoto’s and Hypothyroidism. Could it be possible that you also have Hypothyroidism? This could explain the internal tremors and your slowed movements and muscle issues. I would actually get severe cramps in my upper thighs that would almost make me pass out. I began taking Synthroid for my thyroid condition after having a blood panel run on my thyroid and those symptoms went away. Over time, my tremors and fatigue lifted. If you have a general doctor who will run a Thyroid Panel, have your TSH, T3-free, T4-free, Antibodies and Thyroglobulin levels run. If you’re hypothyroid, your levels will be high and you’ll need medication to level out. I hope this did some good and I wish you good luck and good health!