Amazon applied scientist

Hi, I want to get a job as Applied Scientist. I know it is not easy but I will do my best! What I have to learn to be able to be a good applied scientist? I know that I have to prepare for interviews (LC and ML part), but the most important part is to really be good at the job! Please comment what I should focus on and learn and languages, libraries, topics, I have to focus on. For context, I did a ML PhD in Information retrieval. Now I work as ML PM, so now I want to transition to applied scientist role. I have 2 years to learn in my current company before applying to Amazon. So, I want to maximise this time by learning the right things I have seen that Amazon stopped their Alexa organisation, so should I continue with my NLP specialisation or should I switch to another topic Please guide me ☺️