The last official stats I recall was March in 2018.
Overbuff last time was generally comparable but, it was also wrong some of the time if the interval that Jeff posted on was similar to a week.
What I had written down from back then was that at the top end Overbuff overestimated Winston’s pickrate and underestimated Mercy’s pickrate. At the bottom it overestimated Zen’s pickrate and underestimated Ana’s pickrate. (Winston and Zen at that time may have had higher pickrates with try hard players that are more likely to look themselves up and Ana and Mercy may have appealed more to non try hard players (Ana was lousy at this point in time).
Overbuff scrapes users/gets names from people looking it up and as such is not complete and can have a biased sample. The addition of users being able to have private profiles likely makes this worse.
I personally assume that the trends are generally accurate, the winrate is within a point or so, and that the pickrate might be off by two or so.
You’ll find naysayers to everything Overbuff has to say because it can threaten their personal position on topics.