I had an initial phone screen, then 4 Zoom interviews with colleagues, HR and the manager. While I thought these went well, my candidacy fell into a "black hole." I still haven't heard back.

Don't apply here. Completely ghosted after 2 months and 6 interviews. At first, I thought all was well and I was going to receive an offer. At the last moment, they pulled a bait and switch and changed the job description. They added many new responsibilities and said they were moving the role under a new manager. I interviewed with the new manager, who was very arrogant. After the interview (6 total), I didn't hear anything back, so I followed up cordially. But didn't even get so much as a rejection letter. It's truly shameful.