Before the release of "EA Sports FC24", EA has removed "FIFA23" from all digital stores. Currently, "FIFA23" can only be purchased through EAPlay subscription. EA has not yet provided an explanation for this sudden removal, but this is likely to be related to EA's loss of FIFA's authorization.
The Steam store page of "FIFA23" shows: "At the request of the publisher, EASPORTS "FIFA23" has been removed from the Steam store and cannot be searched." According to SteAMDB data, this change was made on September 21, when the early access of "EASports FC24" was only open for a few hours.