Atmos music is in it's infancy with not many titles available. If it's anything like previous attempts at surround music, it will be bungled and suffer a miserable fate- dying but not dead, limited offerings and leaving a very bitter taste for what could have been. I'd say if you're interested in Atmos for movies, go for it and whatever music becomes available will be a nice bonus. But I think it's a lot of cost and effort to pursue for mainly music and likely to be disappointing.
The good news is though it's been on life support for some time, there is still a decent amount of new music in surround being released and a nice amount of back catalog- though many of those cost quite a bit. IMO your money would be better spent building a collection of surround music with MCH blu-rays, SACDs, DVD-As and DVD-Vs and DTS-CDs. I think you get much more enjoyment bang-for-your-buck. Once you've built that collection to a sufficient level, maybe then think about Atmos. You'll have a better idea of how much and what type of music to expect after a few years go by.
But if you're big into movies and their audio, that's a different story. Or, if you have a good bit of disposable income, that changes the calculus too.
All just IMHO.
Welcome to the forum. You'll find a great community here, very generous and helpful folks and tons of info. And tons of great times to be had if you find surround music enjoyable.