Getting into Dolby Atmos and need some advice.

I am looking to build an HTPC and would like to play Dolby Atmos movie files.Right now i have tried Roku and Fire TV and they do not pass the 7.1 hd. I am using the PS4 and plex right now. It sounds great but i am sick of having to use the game controller when all i use it for is to watch movies not play games. I would like to go back to an HTPC and go back to the KODI software. What would you recommend for the type of hardware i would need to purchase to get a great ATMOS sound and picture. Hope someone can lead me in the right direction.