Start with the fundamentals. I have published on my blog introduction series of articles for beginners (don't subscribe, it is not necessary).

https://stayux.substack.com/s/ux-design

UX is a deep topic. But from software-developer perspective you must cover the basics (if you choose so).

My book recommendation list: Laws of UX: Using Psychology to Design Better Products & Services

https://www.amazon.com/Laws-UX-Psychology-Products-Services/...

Think First: My No-Nonsense Approach to Creating Successful Products, Memorable User Experiences + Very Happy Customers

https://www.amazon.com/Think-First-No-Nonsense-Successful-Ex...

About Face: The Essentials of Interaction Design

https://www.amazon.com/About-Face-Essentials-Interaction-Des...

I hope this helps, good luck:)