Can someone suggest a book or resource to learn more about designing a software system but not "scalable" system design that so many interview prep books talk a

Can someone suggest a book or resource to learn more about designing a software system but not "scalable" system design that so many interview prep books talk about? I'm especially interested in something that is _not_ web related. I've spent most of my career fixing bugs or taking over apps/systems that someone else started. I really don't know how to design something new. (I mostly work on APIs, Android apps/services, and a bit of game middleware).