You could read https://theconversation.com/why-scrapping-the-term-long-covi... which meets these claims head on and highlights why the research is faulty. The Guardian published https://www.theguardian.com/world/2024/mar/15/long-covid-sym... as well which is more truthful.

And of course, if you had not relied on a politically motivated, faulty, non-peer reviewed study you would find the following problems caused by Long Covid:

viral persistence https://www.nature.com/articles/s41590-023-01601-2

Microclots in the blood and endothelial dysfunction (leading to vascular problems, organ failure, cardiac events) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8883497/

Immune system dysregulation https://www.science.org/doi/10.1126/science.adg7942

Mitochondrial damage https://www.news-medical.net/news/20240104/Study-identifies-...

And finally yes, blood-brain barrier disruption https://www.nature.com/articles/s41593-024-01576-9