Sorry to hear you're having a bad time of it, many here can understand the exhausting nature of PCS when it lingers for months. I know I didn't think there was much progress until a year had passed. It can gradually lead to depression, you sound like your confidence is down.

I think your pre-existing condition is compounding things, have you always had low blood pressure?

Have you tried spending a few days without any visual stimulation, i.e. no computer, smart phone or TV to see if this effects your fatigue. I would continue with the daily walks as good blood circulation is important to both and heart and brain. A few times when I did too much exercise I felt like crap afterwards but it passed after a day or two of rest and I actually felt better for it - but it's best to not push too much. Also, I wonder if there are some desensitising exercises you can do?

One thing I notice is that I miss out words when I type with is annoying lol.