I shouldn't have got a PhD. I am not suitable for research in my field. How should I proceed? I shouldn't have got my PhD. I have published 5 papers in Q1 journals. But that has been possible because the topic is hot right now and much rigor is not required for publishing.
I can use an open source or commercial software without knowing how it works in detail and churn out papers. I am just pushing some buttons in a black box and getting results.
I can't teach the numerical method behind the software or the mathematics involved because I never understood it. Other students who work on this field take courses and have thorough understanding of the subject. They go on to teach the subject. While I am poor in mathematics, I am just dumb and lazy to self study it, solve examples.
I am publishing papers now at a decent rate, but I am lacking depth. I am not suitable for my field of research. I don't know if I can do anything about it now.
I recently got a PhD and searching for postdoc positions. I just don't fit anywhere. Everyone wants someone who is expert in the theory or have strong mathematics background. I have neither.
I shouldn't have got my PhD. I think, my advisor, committee and university just wanted to get rid of me.
This sounds like classic Imposter Syndrome combined with end of degree burnout.
What you are feeling is natural, but having a bunch of papers published seems to imply that this is emotional and not a substantial issue.
The job market in many fields is terrible at the moment. Some of the issues in finding a good position are external and will hopefully subside before too long.
I suggest that you talk to a counsellor about your feelings and also push hard in the job market using all available resources, such as your advisor, etc.
Both the feelings and the job issue will pass if you don't let them affect your sense of self-worth.
Depth will come. You have proven that you can learn. The end of your formal education isn't the end of your education.