StreamElements Senior Software Engineer interview questions

Have a very Bad Interview experience with StreamElements after 8 rounds of Interview. Started the process with an external recruiter reaching out for a Senior SWE role. Had two recruiter interview at first stage, one with external third party recruiter and another one with an in house recruiter. Asking questions about experience and interests. Then One take away home project with very strict deadlines (2day), One system design interviews. After this round The external recruiters were asking for expected salary and ensured me that the interviews went really well, and the engineering team was very impressed. Then they requested an interview with an Engineering Director, I was very impressed with him. I felt very connected and very open with the director. The director told me that there is multiple team hiring and I can talk to engineering managers about team selection. After this the external recruiter told me that, everything was very good and I should wait for an offer. But the rounds of Interview didn't finish. Then I faced a behavioural interview round with a Hiring manager. Interestingly at the end of the this interview manager directly told me that he is very convinced and going to ask me for his team. Then I was scheduled with an High level HR Administrator for another interview round, who was asking about my motivations about the move. And If I have worked in a start up mentality work. This round also went good from my side. The external recruiter continued to assure me that this is a done deal, and the HR interview was just to ensure if I meet a certain level for a Higher Comp package. Then I was scheduled for another interview with the CEO. That also went well, the CEO assured me that everything looks good and the HR will reach out to me. After 4/5 days was gone. I got an email from the initial in house recruiter that I am not selected, the cause they showed is -- They have another candidate that have more experience with fast paced start up environment. Where I have been working for big techs for the last 6 years and might not suit the environment. This is the most wired reason I have heard in all my years working in tech. Really are you guys only hiring for 1 role? And then instead of answering some questions both internal and external recruiter ghosted.