Often, your better off with slower clocked RAM if the latencies are better. Ryzen also benefits from lower memory latencies. In other words, DDR4 3733MHz is faster than DDR4 3800MHz which is ordinarily counter intuitive.
DDR4 3800MHz is counter productive as it forces a divider to be used where the Infinity Fabric and memory clocks are no longer synchronous. Going to DDR4 3733MHz for example is good for X570 and Ryzen 3000 series processors. You do reach a point of diminishing returns pretty quickly. Games can take advantage of faster memory to some point. Most desktops simply aren't capable of using that many threads or that much memory bandwidth. This is why moving to quad-channel HEDT systems rarely yields major increases in application performance. Unfortunately, most desktop applications cannot take advantage of it. Faster memory means more memory bandwidth.