Many people recommend the K4, but a large portion of the K4s sold on PDD, Taobao, and Xianyu are fake. They are very difficult to use; the keys tend to lift easily. If you must buy a K4, I suggest purchasing an older model. You can usually find older models on Xianyu for over 200 yuan. These have silver contact points and thicker keycaps, typically made of flat rubber.
Based on my experience, I recommend buying the XieGu VK5. The keycaps on the top row are clear and easy to type with, and the feel is crisp without any sticking. At a price of around 200 yuan (RMB), a new one is comfortable to use. It's the most comfortable keyboard I've ever owned.