Any helpful guide to overclock CPU and RAM x370 K4

To get you started in Ryzen over clocking, I suggest downloading and using the Ryzen Master over clocking utility provided by AMD that runs in Windows. On the same page as the download link for this software is the User Guide, which you can also download and is a must-read guide on basic Ryzen CPU over clocking.

https://www.amd.com/en/technologies/ryzen-master

Memory over clocking on Ryzen, which can also be done in the Ryzen Master utility, is a situation that requires some background explanation. Success in over clocking memory in a Ryzen system is more dependent upon the type of memory chips used in a memory model, and what the highest specified over clock speed is. Samsung B-die memory chips are known to OC the best with Ryzen, Hynix chips in general don't OC as well. If you can't get your memory past 2400 with the XMP profile, the compatibility of your memory with Ryzen is questionable.

All an XMP profile does is automatically set the basic memory timings for you, and the DRAM voltage. Manually setting the same timings will make no difference. What you can do is apply the XMP profile, and "loosen" the basic timings when you increase the memory speed. No one can tell you which timing are optimal, you can only discover that by trial and error. Choose the loosest set of timings (highest numbers), and IF they work, you can TRY to reduce them for better performance, but you'll reach a point where the PC won't POST or boot.

Any memory over clocking is not guaranteed, and your memory model and its timings were designed to work with Intel X99 and Z170 chipset systems. How well it works with Ryzen will be basically luck. Start with the  DRAM Voltage should be set to 1.35V, and the SoC voltage should be increased from the standard 0.9V to 1.1V - 1.2V.