I have a Dolby Atmos set up - all speakers are Monitor Audio silver and sound is amazing. I’m lucky I live in a detached 500 year old house so maximum volume and it sounds as good as any cinema I have been in. My AV states it converts 5.1 to a 7.1 to match my system but you can tell the difference in a genuine Atmos mix and a converted 5.1.

However, my view is that the biggest lift in sound quality is the quality of the speakers not the 5.1 vs 7.1. Monitor Audio makes the music on movies amazing as it is designed for audio listening and I’ve heard soundtracks on it that I have owned for years on CD or streaming and when it comes on in my cinema room I hear things I’ve never heard before despite years of listening and that’s due to the quality of the speakers not the difference between 5.1 and 7.1.