I think people who haven't had a chronic condition (including doctors) tend to underestimate the impact they can have on your life. Long COVID symptoms may not be "severe" or "serious" in a medical coding dictionary, but those terms in a medical dictionary are quite distinct from their everyday meanings.
The best evidence we have seems to be that somewhere very roughly around 20% of people who get infected (vaccinated or not) get it -- more if you're older, less if you're younger. Experts don't seem to be willing to say much about what fraction of those people will have symptoms forever, or to what extent (very happy to hear otherwise if somebody knows better!).
While case numbers are high again (in the UK) and with the more infectious and virulent Delta variant having replaced others, it's not totally clear to me that the risks from long COVID are even all that much changed since before the vaccines.