How do I discover Islamic books that go beyond the basics?

Assalamualaikum wa rahmatullahi wa barakatuh. Lately, I’ve been getting tired of reading books by non-Muslim authors. I’ve tried ones on influencing people, daily akhlaq, business, and so on. But every time I come across advice like “listen carefully when someone talks,” I think to myself: the Prophet ﷺ already showed us this. Why am I learning it from others instead of from his example? The problem is, when I look for Islamic books, they often feel too simple or even childish. Take *Enjoy Your Life* for instance-it’s wholesome, but it stays at a very basic level with everyday tips, almost like it’s written for first-time readers. Then there are business topics. I know Umar ibn Al-Khattab was incredibly successful in trade, but I don’t know of any book that breaks down his strategies, principles, or methods. Where’s the in-depth stuff? I’m not asking for specific recommendations here. I just want to know how to start searching for Islamic books that aren’t too elementary or repetitive. Since I can’t spend a lot, I need to pick the best ones each time. Any tips on finding that middle ground between shallow and super scholarly? Jazakum Allahu khairan for any suggestions.