Elgato Game Capture HD60 S+ has different maximum recording bitrates depending on software used.
Game Capture HD on macOS: Up to 45Mbps at 1080p 60fps.
4K Capture Utility: Up to 60Mbps at 1080p 60fps. Up to 45Mbps when using HDR.
Third party software (such as OBS studio) will receive uncompressed video from HD60 S+. As a result, there is no defined maximum bitrate in third party software.