I don’t use Sonos or any other alphabet soup format for my TV audio, so there is that caveat, I get good enough sound from the TV via a stereo amp and two good HiFi speakers.

But you are asking two questions, and I can answer the one about compressed and lossless audio for music play. As long as compressed does not mean the lowest MP3 quality, and means something like Apple AAC 256 kbps or better, you will not hear any difference between that and lossless using Sonos or even better kit. Differences are buried in the room ambient sound levels even in a quiet room, and it may take high quality headphones for these to emerge. This can be established in a well conducted blind listening test, to get subjectivity out of the way.

Your other question relates to getting Atmos effects, that you do not get today? In this case, I am sure that sound differences of Atmos over less advanced TV audio systems are not subtle, but will Atmos that is not achieved via speakers actually placed above/behind you be good enough to justify the additions you are thinking off, is still a subjective thing that will have more posts here offering their subjective views.