I got my PhD earlier this year. I have been productive during my PhD, published 4 papers during my 5.5 years duration in decent journals. My advisor was not an expert in my area of research, so my research ideas, methodology and analysis were completely isolated endeavour. This helped me become independent researcher but it also made me seriously unconfident in my technical know-how and research abilities.
My PhD was on a different field than my Masters and Undergrad degree. I took some courses to come up to speed, but I did not do many of the necessary courses because I thought I could self study them. I did self-study, but since I did not give exams or diligently solved many exercises in the book, I have a gap in the understanding of the core fundamentals of my field.
For example, one of the course I had to self study was numerical methods. I read the theory, made notes, did some exercises. But only retained a part of the subject because I had to add Newton-Rapson method in my code, so I just remember that.
Similarly, another course was Finite element method. I read the theory, made notes, did some exercises. But only retained a part of the subject because I did not have to develop FEA codes in my research. I used an opensource solver and focused on getting results for my research.
All these half-baked fundamentals made me realized that I am not equipped well for a career in research. I get overwhelmed when I start to revisit the fundamentals now. I feel I missed my chance when I should have studied more seriously and asked for help for the topics I was facing difficulties.
I had so much time in PhD to improve my knowledge and technical knowhow. After PhD and during postdoc, I am finding it harder to concentrate as I have to produce results at a much faster pace than my PhD and I cannot dedicate time to study and develop fundamentals. How to address this knowledge gap after a PhD?
Please don't say its imposter syndrome. I am just asking on how to improve technical/fundamental knowledge outside a university environment? Because, I feel it is not possible to gain deep understanding about a subject without the university/classroom setting.
I am really troubled and am worried about my career prospects. I have been looking for jobs in industry and at the moment I am not getting responses. So the postdoc position I am in currently will support me for the next year. However, I have to find something till then. If I don't have confidence in my abilities, none of this would matter. I would not be able to get a job.