Elgato Game Capture 4K60 Pro MK.2 has different maximum recording bitrates depending on software used.
4K Capture Utility:
Up to 140Mbps at 2160p (4K) 60fps in AVC/H.264
Up to 105Mbps at 2160p (4K) 60fps in HEVC/H.265 (HDR Recording) - Learn more about recording HDR with 4K60 Pro MK.2
Third party software (such as OBS studio) will receive uncompressed video from 4K60 Pro MK.2. As a result, there is no defined maximum bitrate in third party software.
For more information on adjusting color format in third party software: Elgato Game Capture 4K60 Pro MK.2 supports RGB 4:4:4 Video Output