Ansys Operation Analyst interview questions

went through multiple rounds of video interviews scheduled a few days apart. First interview was with two people, second interview was with two as well. Both of these lasted an hour long. third interview is where it got interesting. it was a video call with 7 other people whilst you give a 3 hour presentation of yourself and they each take turns throwing questions at you. after all the interviews and vigorous questioning, they completely disappeared. I have tried following up specifically with a manager and he responded saying to give them a few days as they have other candidates which is understandable unfortunately after weeks, they ghosted me. I have not received any word back, which I believe is highly unprofessional being that I have dedicated more than enough time to the interview process. after a total of 5 hours interviewing the least they couldve done was send a rejection email