That is a good recommendation. It also implements a Chromecast receiver, which seems to work better with Roon than the AirPlay receiver implementation does.
All told, this is interesting because recent Fire TV models, such as Fire TV Stick 4K Max, have multichannel Alexa Cast sender functionality, thereby providing an Alexa Cast bridge between Roon and Echo devices. I just confirmed that this works properly even with an Echo Studio stereo pair.
AJ