Spoke to the hiring manager directly first, no HR. Had a long chat and I was invited to speak to other members of the team. Had two more calls over the following weeks. Never heard anything back. Sent two follow up emails. Ghosting is very unprofessional and there's never an excuse for it. I think the team was screening me, I have no idea as all the "interviews" were very casual and in hindsight, disorganized.