Good that you are recovering quickly. My wife and I also recovered very quickly with few symptoms. Just elevated temperature which peaked in one day, me with a one day runny nose and her with a one day headache. Actually hardly sick enough to be called sick. But in our cases it had been nine months since the 3rd (booster) shot of NVAX in the crossover trial.
I'm not qualified to make comments like this but I'm doing it anyhow and don't know how much of it might be valid:
-- You contracted a recent variant which evades early prototype vaccines.
-- You may have been "imprinted" caused by former mRNA jabs.
-- Some individuals just don't develop robust immunity from vaccines.
-- NO Covid vaccines are sterilizing and you can still get the bug.
-- Any or all (?) of the above.
-- Notwithstanding all of that, if fully vaxxed, a person may still have gained enough protection to avoid very severe illness.