They don’t care about prior knowledge, skills on infrastructure, databases or even abilities to create services. Only care if you can solve dynamic programming problems with silly scenarios that you likely haven’t had to worry about if you are a good programmer during your career. I would recommend they move to something more credible, like a take home code challenge that has you build a simple web app or a backend challenge that has you build a simple service with REST endpoints. Think this will dramatically improved the quality of the developers they hire and their review process.

The interview was very much nontechnical. They mostly wanted to see if you are a good fit for the work environment and you have a vested interest in programming. They will ask you to back up any work experience/projects listed on your resume.