A users settings in Roon have to match the devices capabilities to get the desired results.
Nowhere does it read that the device is capable of acting as a renderer only and Meridian is known for that incapability for quite some time already.
See also;
UPDATE: I spoke to soon, seems like Meridian pushed out a set of new Firmware at some point. So rendering only should work but because they can’t authenticate the stream they don’t display MQA: