We are in agreement to restrict the discussion on this board to NPA theory of personality. But to answer your post, the Wikipedia article is interesting.
But science is an ongoing quest where hypotheses are brought up, tested and new hypotheses formed.
In the case of ABO and personality traits, there is some work being done still despite the current lack of consistent validation. Here's an example of a study that was done in Japan about a hypothesis of mine that ABO B is associated with low DBH activity and low Persistence trait. Their findings included that ABO A was associated with high DBH gene activity and Persistence ( a Cloninger personality trait). So we will keep reading about this.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0126983