3DCenter.org has published an AMD Zen block diagram "with little speculation". The diagram was drawn up from a software patch published by an AMD Technical Staff member called Venkataramanan Kumar.

AMD Ryzen 4000H Renoir Block Diagram Confirms GPU PCIe 3 Limitation For Gaming Laptops by Paul Lilly — Thursday, July 23, 2020, 11:03 AM EDT Comments ...

Please do keep in mind that only Ryzen 3000 (Zen2) will open up X570 to the CPU at PCIe 4.0 x4. If a Ryzen 3000 of the Picasso family, as an APU based on older architecture, are used, the chipset ...