Instacart Software Development Engineer (SDE) II interview questions

went through 4 rounds of tedious interviews. Passed all coding rounds with no rounds left. Finished the system design and the interviewer said he didn't have any other questions so we spoke about something else. I was still rejected. Given others had similar experience, they're no really hiring, just interviewing to make it seem like they have open positions. Massive waste of time and effort IMO