I always figured that the president of the European Commission is a member of the European Commission but I wasn’t 100% sure if that is “technically” the case. I did some research and The list of Members of the von der Leyen Commission¹ clarifies that the president – along with the vice-presidents – are included among the 27 members of the “College of Commissioners”.

¹ https://commission.europa.eu/about/organisation/college-comm...