Technology Innovation Institute interview questions

I was contacted via LinkedIn by a recruiter who provided a description of an open position that looked promising. Consequently, I accepted the invitation to proceed with the interview process. The interview consisted of four highly technical stages, covering topics such as cryptography, system architecture and design, C++ internals, and overall candidate experience. In summary, the interview process was challenging, but it was a pleasure to engage with experts in each field. I successfully passed all stages, which took a total of 10 hours, not including preparation time. However, I did not receive any communication from them until I reached out a month after the final stage to inquire about the status of my application. Their response indicated that I had passed all stages but that the position was on hold due to pending decisions from the hiring team, which coincided with a period of significant tech layoffs. Unfortunately, after 10 months, I never heard back from them. It's disappointing because I had a positive impression of the company, but I don't understand why there was no communication from HR, especially considering the substantial investment of time and effort from all parties involved in the interview process.

A HR sourcing company contacted me on LinkedIn. Asked for my resume and had a short call explaining the process. Then there were supposed to be three rounds of technical interviews but after the second round there was no response for over a week. On emailing them, they said I had not been selected.