Expedia Group Software Development Engineer II interview questions

Initial call with HR, One hacker rank challenge. After 2 follow-ups I was told that I would be moving to a virtual 4 round interview. after few days received an email with scheduled interview rounds without asking if I am avaiable to interview for that day, but there is an option to re-schedule it which I used as I had some project deadlines. What I don't understand is why will Expedia HR not reach out to us before sending an email with the interview schedule? Later came the virtual interview day, interviewers was cool and asked about past experience, system design, and ds questions. I did decently well and was expecting a positive response. Now here is where my overall experience became negative. I have not received any update/feedback regarding the interview outcome for 1 week. I have sent a couple of follow-up emails asking for interview result. Finally, I receive an email from HR saying that she is following up with the Hiring Manager, first forward two days still no update from HR, I just checked the workday portal which says not selected, which I understand it could of many reasons. What I don't understand is why would they not take some time to send an automated email or take some time to let us know how the interview outcome when we take time out of working hours to interview with them. The sad part is the HR previously worked for Google and was expecting more from her.

The hiring process was not very big and not very small, there were 3 rounds of interviews one technical and 2 manager. The interview was more about my past experience and new aspirations.