ThoughtSpot interview questions

First two zoom Interviews with two different hiring managers learning about my background. Both were quite impressed with my background but had a concern about me being overqualified for the role and will I be staying for a longer time or will switch to different department? I very well explained what is in it for me in that position. I was later given a home assignment followed by final panel interview and role play. I was mentioned by both of them that they do not have doubt of me not suitable for this position and liked my profile so much that I was even provided the salary during the interview. Also, I was asked to confirm the next day about the salary along with 3 references. Hence, next day I mentioned about my salary expectations which was open for negotiation. But I was shocked to discover the very next day after following up ,that the offer has been sent to another candidate. The reason being given we were looking for candidate who would basically jump in for a much lower salary (lower than the market avg. and initial salary mentioned to me). When I said if salary is the concern, I am ready to compromise but I was not able to understand the confusion of not hiring me. Later, when asked about my feedback, I was said I deserve much more than this and wasn't given a satisfactory response which was quite unprofessional. Had this been the case, I should be rejected after very 1st interview post resume selection. The concern was always lingering about me being over qualified and was still went ahead with the complete process. I was bit disappointed the way it was handled as I literally spent considerable amount of time for the assignment which was highly appreciated by both of them couple of times during the interview. I really liked the vibes of both the young hiring managers and found them amazing but wished HR to be involved at later stage for regulating it professionally ensuring a fairer treatment. I am yet to get my feedback which would help me in improving my performance.