I’m not familiar with that anime but judging by the information here, Jujutsu Kaisen (TV) is the normal series with 24 eps of normal length and this is an ONA with 3 eps. I’m not an expert with ONAs as well but I guess those are either like longer OVA episodes or in the contrary pretty short specials or something. It says 1 min. length but I’m not sure if this info is correct.