This restriction is no longer present. With Firmware 21.1b you can play Qobuz Connect in QRONO d2a mode on supported models (also true for Tidal Connect, Spotify Connect).
In QRONO d2a mode, if you encounter MQA albums from Qobuz Connect / Tidal Connect / Spotify Connect, MQA will also be decoded. There are still more MQA albums from Tidal than Qobuz / Spotify.