Thank you for your reply. I've done a bit of research in the meantime. I wrote to AMD about this and they pass the 'blame' to Lenovo (or any other manufacturer):
"Please be informed that AMD Ryzen Mobile Processors with Radeon Graphics have been widely adopted by global notebook PC manufacturers, with each adopting individual customizations for each notebook design or series. Due to the customization, which includes specific software feature support, the generic software driver package from AMD is not supported on those notebook PCs.
Hence, we request you to contact the laptop manufacturers (Lenovo) for the compatible drivers"
So I had to move over to the Lenovo forums to dig a bit deeper to see how I can solve this. At the moment some video issues were solved by updating the BIOS. I'll dig deeper to see if with the new BIOS I can update the video driver also.