The Covid-19 Jigsaw: 2+2=5?

I am and never have been, a specialist on viral infections. Before my retirement, however, I spent a lot of time looking for patterns in masses of diverse psychobiological data. So, although it may be premature, I would like to attempt to tie together some information relating to the Covid-19 pandemic, which makes a kind of sense (at least to me). The facts appear to be, as follows:- 1. When it infects, Sars-CoV-2, seems to have variable effects on different patients; 2. In some patients (notably a majority of young people) it has modest (sometimes even asymptomatic) effects; 3. In other patients (especially older people and those with 'underlying health conditions') it can be life-threatening, with damage to a variety of organ systems (including the lungs, digestive system, circulatory system and even the brain); 4. Some patients (not just the elderly and seriously ill), develop 'Long Covid' with impacts on one or more organ systems, that can last for several months (at least); 5. An early study carried out across NHS hospitals, showed that the safe, cheap, immunosuppressive steroid, dexamethasone, was helpful in preventing some of the worst symptoms in people with this viral infection. This compound is routinely given, at least in the UK, to badly-affected patients, who often appear to be showing excessive immune responses; 6. Studies (Edinburgh University) have revealed that at least 5 genes increase a patient's chances of developing a clinically-challenging infection with Sars-CoV-2. Some of these genes suggest that other drugs e.g. an anti-arthritic might be beneficial in treatment; 7. Studies (Yale University) have linked clinically-challenging infections (and possibly Long Covid?), to the production of autoantibodies (antibodies directed at the body's own tissues); 8. There are a number of autoimmune diseases (e.g. Crohn's disease, Grave's disease, Lupus, Rheumatoid arthritis et cetera) where the body stops recognising parts of itself as 'self' and attacks the organ and 9. Autoimmune diseases (particularly arthritis) have genetic predispositions but are also produced by accumulated damage, especially in older individuals. It seems possible that the life-threatening effects of certain Covid-19 infections are either a) directly triggered by possession of autoimmunity genes or b) the viral infection changes proteins in particular organ systems, which then activate a full blown autoimmune response (in people with a predisposition for the condition?).