There is some confusion here. Roon Ready is not just that it uses RAAT this is purely the transport mechanism between core and endpoint, bridges use RAAT to move audio data and a USB DAC to. Core uses RAAT.
Roon Ready means the device in question has Roons proprietary SDK built in to its own operating system and connects to Roon over the network and plays audio to it via the network like UPnP, Spotify connect, AirPlay or Chromecast. It has more of an oversight of the device it’s built into and its capabilities it also has been tested to work as it should. It has input context switching abilities, power control. It can control volume if it’s an all in one amplifier, it can control volume of certain dacs or streamers if the OEM gives access to an inbuilt preamp.
Roon Bridge is purely a Roon software player layer for general operating systems and has no insight into the device it’s installed on only the outward DAC its connected to via USB, spdif, aes are one way only and can’t be known to Roon. it may be also possible with i2s not sure on that interface. You are more open to issues with bridge as not all os are equal nor support all formats in the same way on the same DAC.
Any device that uses an off the shelf Roon capable board such as converse digital or BluOS does not mean it’s Roon Ready out of the box. All devices with these existing streaming cards have to be fully certified as there is more to Roon Ready integration than just playback.