For any single interaction, your risk of virus transmission is probably lower with a vaccinated individual than with an unvaccinated individual (although the magnitude of the difference is unclear). But unless you're living as a hermit you're going to be in contact with thousands of people over the next several years. Some of those people will be infected and contagious. So you will inevitably be exposed multiple times.
If you have two population groups A and B and A has a massively lower infection rate then population group A is not going to have the virus surge through the entire population.
But this is all veering off my original point that you can’t claim bodily autonomy as a reason/right to not take preventative measures like the vaccine if you aren’t actually being autonomous.
What do you mean by common? Do you mean that it happens or that it’s the same rate of infection as being unvaccinated? Your argument only works if the breakthrough infections are as “common” as getting infected without the vaccine.
> Whether we're exposed by a vaccinated or unvaccinated individual is irrelevant
But it is relevant that the chance of a vaccinated individual being contagious is _massively_ lower. You can’t argue that breakthrough infections of vaccinated individuals exist, so therefore coming into contact with a vaccinated person is as risky as coming into contact with an unvaccinated person.