Though it is worth noting there is experimental clinical data providing a plausible pathway to suggest long COVID is a result of cell activity dysfunction with plausible biomarkers of dysfunction, and we've known this long enough to know long COVID is a real medical pathology (one distinct from acute infection based on biomarker evidence):
Elevated vascular transformation blood biomarkers in Long-COVID indicate angiogenesis as a key pathophysiological mechanism, https://molmed.biomedcentral.com/articles/10.1186/s10020-022...
Plasma Proteome of Long-covid Patients Indicates Hypoxia-mediated Vasculo-proliferative Disease With Impact on Brain and Heart Function (Preprint), https://assets.researchsquare.com/files/rs-2448315/v1/8043bd...