W/respect to booster shot side effects being less than 2nd shot side effects, I wonder if there's a selection effect at play. Anecdotally, I know of a few people who would I have otherwise would have expected to get booster shots, who are holding off from now because their reaction to the second shot was on the worse end (e.g. multiple days of fatigue etc.). Presuming a correlation between 2nd dose side effects and booster side effects it may be that the population most prone to getting side effects from the vaccination is less likely to get the booster. Would be curious if that study was looking at a particular cohort of people (or is such a study will be conducted in the future) to avoid that sort of confounding.
I'm a bit more worried that it's yet another step towards atomization. With churches and general community organizations already dying work remained one of the few places where people met a set of, at least relatively speaking, non-selected other people.