Columbia University Irving Medical Center interview questions

The interview process was long and drawn out over an entire summer, and after 4 rounds (two in person) I was completely ghosted even after following up after the final round, with no rejection explanation or anything. Very unprofessional ending to a long process, felt disrespectful to the time interviewees take to prepare and attend interviews to not provide any feedback or form of explanation. After this experience, would not personally apply again or recommend others to apply.

Applied online, got a message back after 2 weeks. First interview went wonderful. Second interview few weeks after, in person, went great, I really liked my future team. Did not hear from anyone till almost a month later, I was asked for references from previous job. Provided them same day. After 3 weeks of silence got an email invitation for a phone conversation. Received verbal offer, but politely asked to re-negotiate, I pointed that I would have less PTO than at my current job (similar position) and that Columbia would only start 401k matching contribution after 2 years of work (recruiter confirmed both). I asked for a bit more that their yearly contribution would be for my salary (to compensate at least partially for the difference). Recruiter admitted they were valid points and promised he would consult with his superiors and get back to me soon. I did not hear from anyone since (it's been 3 weeks). I think that, after almost 3 months of recruitment process and a verbal offer, a candidate deserves at least brief courtesy call to let them know they are no longer under consideration. It is really sad, because I liked the job so much I was ready to accept their initial offer, if they would have gotten back to me and let me know they couldn't offer me more. I did not expect to be ghosted at this point of the hiring process.