how to improve product thinking?

Specialization is a dangerous trend. Even at big companies, having fairly generalist designers who can do copywriting, do at least some basic user research, design an icon where you need one, or work with an illustration team and understand what makes a great illustration, that breadth matters more than people admit.

If you want larger influence in your organization, if you want to gain seniority and be truly effective, you are going to need to know a little about coding, a little about graphic design, a lot about user interface and product design. Because if you want to work as a product designer, your project is to ship great products. That requires either a huge team of specialists or some generalists who can work with specialists and create a very effective dynamic team that can solve the right problem in front of them.