1st phase is a short technical screening with mostly low-level sysadmin questions by an engineer with a strong sysadmin background and several years as DevOps. The topics are Linux, Networks, Docker, and K8s, but all questions are about what is under the hood - encyclopedic knowledge that you never use as a cloud engineer and can Google quickly. If you didn't learn by rote or forgot, you will not pass. At least it takes 15 minutes.