The next version of Steam Link for macOS is now available as a beta build.

You can opt into the beta on TestFlight by clicking on the link here:
https://testflight.apple.com/join/Cye7Gfyy

New in this build:

• Added a 100 Mbit/s bandwidth option
  
• The "Unlimited" bandwidth option allows adaptive bitrate up to 250 MBit/s when connecting to Steam beta dated June 10th or newer
  
• The enhanced quality presets have unlimited bandwidth
  
• The client log is now available in:
  ~/Library/Containers/com.valvesoftware.SteamLink17/Data/Library/Application Support/Valve Corporation/SteamLink/streaming_client.log