Pretty standard interview process (HR screen, competence, team fit etc) however communication from talent acquisition went from being amazing to pretty poor. Constantly chased and it took ages to hear back

Initially, it was a fast process, I was told they wanted to make a decision before the holidays. I had a phone screen with an HR manager, then a call with the Hiring Manager, and then the following week I had 3 interview rounds, including a 30-minute case study presentation. The HR person I was dealing with was very delayed in her responses. I asked when I could expect to hear back about the next steps and I didn't hear from her until over a month later (despite sending 2 follow-up emails). I sent a 3rd follow-up email over a month later and within hours I got an automated rejection email. The HR person never provided any feedback or insights. They say they want to hire from Amazon/Google and they clearly model their hiring process after Amazon (all questions I was asked were based on Amazon behavioural questions), but then treat candidates this way after 4 interviews and a presentation, it's really unprofessional. To have a candidate go through this amount of prep to be ignored and then given a templated thanks but no thanks email showed me all I needed to know about their HR/recruitment process.