[martiya]

Clearly you have moved to a better league and your performance has dropped because of it. It does not mean you cannot improve and cover that gap. Maybe just because of your environment or background you have missed exposure to learn what you now see you are missing. Now that you see what you are missing go and fix it. Knowing what you lack is a good first step.

Do not give up so early thinking on changing roles unless this is what you want to do. And notice that PM requieres a different set of skills. I even dare to say that the knolwedge gap could be bigger moving to a bigger company and in the way taking a new PM role. And learning PM without experiencing the role is even more difficult.

If I were you I will get a good book or on-line course and work on it on the side. Go to the sylabus of some good university course or some online course of the same sort and get some funcdamentals of computer science on algorithms and data structures. It might take you a number of months but you will enjoy and learn from the begining. The type of mistakes you say you did in that first role are pointing that you need some fundamentals.