Hi Johanna,
I can relate to much of what you've said - especially about pacing, crashing and massive reading, especially of medical abstracts, of everything I can get my hands on about Long Covid. I am leaning toward another major medical theory about Long Covid causation - microclots. Medical evidence in the US, UK, Germany, South Africa and elsewhere has led to the conclusion the microclots produced during viral illnesses and normally dispensed with during the recovery process, linger in Long Covid patients. The theory is that these microclots prevent necessary oxygen from being adequately dispersed organs within the body, resulting in the shortness of breath and brain fog common to Long Covid patients. There's even an experimental treatment in Germany and UK where and apheresis process to remove blood, "cleanse" it and return it to the body. Results are mixed. Based on this medical research and experimental treatments, I am trying donating blood to see if it helps my symptoms. I had never donated blood before and will be alternating between donating whole blood and also plasma and "power red". The later two use process similar to the apheresis Long Covid treatment. Just started, but noticed some improvement and will be further chronicling any changes and healing with upcoming blood donations. Worst case - I'll be saving lives by donating blood.