People often die shortly after retiring partially because of a lifetime where they could've been able to maintain their health and hobbies and lifestyle that allowed for workless living, except work demanded the majority if one's waking hours...
Um, the spike in deaths shortly after retirement is not explained by your theory.
Having your social life completely defined by and contained by work does though.
The shift to working from home, then, should provide a spike in deaths related to social isolation?
That would seem likely, as loneliness and social isolation have a much higher risk of mortality whether they have underlying conditions or not.
is it explained by the intuition that people who are about to die from various frailties first find that they are too frail to work and thus retire? (no part of which i am moralizing about, just seems to make sense)