I want to explore the banking/financial industries more for potential career options, can you recommend any books/ free online courses and sources in general as a starting point to build on my knowledge and understanding of these areas (which is basically starting from zero), for now I want to read more broadly and have a better understanding before narrowing it down. So would I learn about markets, trading, and also economics concepts, and would you be able to recommend any topics that I should focus on for practicality rather than having to read topics which won't be as relevant?
A great starting point is "Fundamentals of Corporate Finance", Ross, Westerfield & Jordan.
This book will give you a good overview of key concepts in finance. This book is widely used in introductory courses for non-finance majors, to both teach some fundamental ideas, and give a panoramic view of the field.
"Trading" will probably be the topic that is less developed in the book. This is partly because there is no bullet-proof method for trading, to some degree it is an art, and also becuase some of the useful techniques for trading are too advanced for an introductory book. However, after reading this book you should have a good sense of the key idea behind the decisions to buy or sell a financial asset.