Hi there- I don't have experience with either of those medications, but I do have experience with brain fog...

Recently, I've been reading about guanfacine being researched and used as a treatment for brain fog and cognitive function in long COVID. Apparently, it has a history of being prescribed off label for TBI for the same reason. It's originally an ADHD medication. Since you were considering options that sounded similiar, I thought I'd mention it. I read about it here, and it includes a link to the summary of their case studies too: https://medicine.yale.edu/news-article/potential-new-treatment-for-brain-fog-in-long-covid-patients/

I'm not sure if you've heard of or used LDN (low dose naltrexone)? That is what I use for fatigue; it helps me with brain fog but I notice the difference mostly in my fatigue. I noticed an immediate difference the first day. It's prescribed off-label from a compounding pharmacy, which can make it harder to persuade someone to prescribe it if they're unfamiliar. But it's been used for various chronic pain and some autoimmune conditions for years. It's thought to have an anti-inflammatory effect.

If you're not familiar, it's dosed at a tiny fraction of the dose of regular naltrexone (down to a few milligrams or sometimes less). At that dose, it's thought to increase endorphins and regulate glial cells, which when overactive are thought to contribute to chronic pain and inflammation. If you're interested, there's a helpful discussion of it here: https://connect.mayoclinic.org/discussion/ldn-dosing-for-fibromyalgia-and-mecfs/ Some of the posts also include links to other resources and studies.

(I totally won't be offended if you're not interested in either or tried both, but I just thought I'd mention it because LDN really helped me and I almost wouldn't have learned about it.) Wishing you all the best!