AMD promises Polaris and Vega based GPUs will receive PlayReady 3.0 support sometime later this year. For the Vega-based APUs there's a more specific timeframe; Q2 2018.
However, as AnandTech reports, it's pretty complicated to ensure your PC is fully compatible with Netflix 4K/HDR. The list of required items is really long:
Unfortunately, there is no succinct way to translate how this affects consumers. The complete PC landscape for PlayReady 3.0 support and Netflix 4K/HDR streaming capability has grown increasingly complicated, despite Netflix’s initial announcement a couple years ago. Building the right HTPC setup for 4K/HDR/UHD Bluray is rather involved. To recap, the following items are pre-requisites to stream Netflix 4K content on a PC:NVIDIA GeForce GTX 1050 (with 3GB) and higher GPUs support PlayReady 3.0, and Intel supports it via the integrated graphics of its Kaby Lake processors.Windows 10 Fall Creators Update (for HDR or using discrete graphics) Windows 10 HEVC Media Extension, or equivalent (if missing due to Fall Creators Update) Latest unspecified Windows Updates Microsoft Edge or Windows 10 Netflix application Netflix plan that supports 4K and HDR streaming High or Automatic Streaming Quality in Netflix Account Playback Settings Minimum internet connection speed of 25 Mbps 4K display with HDCP 2.2 capability HDCP 2.2 certified cable with 4K capable digital interface HDCP 2.2 capable and 4K capable digital interface port on motherboard video-out or discrete GPU Supported discrete or integrated GPU (PlayReady 3.0, HDCP 2.2 output) Appropriate graphics driver