I found it in the information about how it's calculated on kassiesa (which indeed is a single person project afaik)... apparently both numbers correct
"Matches in qualifying rounds are awarded with 1 point for a win, and 0.5 point for a draw, but only for the country coefficient. Clubs that are eliminated in qualifying rounds of the Conference League are rewarded with a number of points for the club coefficient based on the reached (qualifying) round."
So for the individual club ranking West Ham indeed got 29 points, but for the country coefficient they won 31, the difference is the two qualifying playoff matches they won
I guess in a way it makes sense in a way, because this way clubs aren't awarded for being so bad that they have to play the playoffs instead of directly qualifying through their leagues.