How can I improve the quality of my code?

I've been working in cloud infrastructure for the past 4 years and am looking to make the shift into software development (backend).

Although I've written code before and consider myself a developer amongst infrastructure architects, I've never released production-ready software. All have either been POCs or extensions of existing libraries used by other teams. I want to make a career move into software development, with a plan to progress into leadership in that field, but I've become aware that my limited experience working in a team of experienced developers has hindered my ability to write well-architected code.

How can I develop this part of my programming skills if I'm not working with a team of developers in a professional setting? Any books/courses I can take? My target is to land a role as a software developer in the next 6 months (hopefully not too ambitious!)