(There's also research into a genetic link to genes causing dementia so it could be, for example, that those younger who are more susceptible to covid have that gene)
It's also (some even say, primarily) a vascular disease. Surely your 'research' brought up that? People with undiagnosed heart disease, people on statins, people with diabetes 2, etc, are often at increased risk of vascular dementia, for starters; and middle-aged people with these disease risks are also turning up with more severe forms of Covid, and others even younger are simply dying due to Covid-related strokes or being left with damaged hearts, etc.
Genes, by the way, account for only a small percentage of dementias; mostly it is lifestyle related; and even with genetic markers that increase risk, lifestyle changes mean one doesn't necessarily develop dementia, or that one develops a less aggressive progression.
How disgusting of me
Yes. Go read the NHS thread and grow your tiny black heart into something resembling the start of a human's, would be my recommendation.