A few "yes, but..."s:
> If you're not traveling outside the US and living a fairly normal life
Globally, given an at-least-middle-class lifestyle (and any other years than 2020–2021), "not travelling outside [your home country]" is actually rather abnormal. It's mostly an American thing.
I've seen it hypothesized that higher risk-aversion from a media-inculcated culture of fear could be responsible for Americans' unique disinterest in international travel.
If that were true, then "properly calibrating your risk-aversion" as we're talking about here, would potentially result in the average American desiring to travel a lot more — which would then mean that the extra vaccinations would have rather more justification.
> Should every sexually active person take PrEP regularly since HIV is a potential risk to everyone? No, there are populations of risk exposure where it makes sense though.
I mean, if we just had a huge supply of PrEP laying around so that we could afford to be wasteful with it, we could just give it to every sexually-active person for a while to stop transmission, and so effectively eradicate HIV. (Everyone already infected would keep taking it until death, but nobody new would be getting infected, so as soon as all those people passed away, there'd be no more HIV.)
Personally, I'd see it as my duty as a citizen of the world to participate in a program like that. I want to live to see that virus die.
But moreover, doing so would eliminate the risk of anyone ever contracting HIV again; which doesn't just have personal consequences for arbitrary individuals from the population; but also has societal effects (in any country with socialized healthcare), and even cultural effects (in terms of changing the landscape of sexual mores.) Those effects could have net-positive utility that greatly outweighs the personal calculus of "am I more likely to get HIV, or an iatrogenic illness from PrEP." (I don't think anyone's done the true cost-benefit for the societal-level effects. It'd be interesting to see.)
See also: the argument to eliminating homelessness. Where, in that case, the societal-level "economically externalized from the individual" effects (e.g. fewer unpaid ER visits per homeless person) clearly do come out highly net-positive, such that we should strive to do that even if such programs were economically net-negative per homeless person. Thus thinking like "just give every homeless person a house."
> Your dentist only takes x-rays every so often because the x-ray exposure increases risk of various forms of cancer.
X-rays are an outmoded technology, though. If we could make MRI machines cheap enough, dentists could do what they do now with X-rays, by instead taking MRI captures and using a spectrum that highlights the bone-density sections.
In that hypothetical world, there'd be no downside to getting a new MRI every time you visit the dentist.