GiveWell Senior Researcher interview questions

A GiveWell recruiter sent me a message on LinkedIn asking me to send her my resume. She then invited me to complete an uncompensated, online, 45-minute skills exercise. The platform automatically exits you from the exercise after 45 minutes. After two days, I received an e-mail saying that they decided to consider other candidates who were better suited and that people not accepted after the exercise would not be considered for other senior roles. I did not have the opportunity to talk with a human being and did not receive feedback on the exercise.

Overall negative experience. I've emailed a few times to ask for clarification during the process and I've never received a response. I've done two written assessments. One of them was 4 hours long but at least it was paid. No explanation on the criteria or feedback, which is very odd for such long assessments.