The latest Claude is even slightly better than gpt4o, and you can use it for free.

UX is not primarily about how your project looks like, but about how easy it is for humans to interface with it.

On the other hand, user interfaces that are difficult to read or have misleading layouts can seem ugly.

I can recommend the book “the gamer’s brain” by Celia Hodent. Maybe this blog post of hers can give you a rough idea what the book will cover. Although she focuses on games, the lessons are universal.