How are you getting your surround sound?

That sounds awesome! How are you getting your 4K movies on the AppleTV? Trying to determine if most people stream their movies now or still popping in a disc.

Via Apple TV device. Although when traveling I may use my iPad or MacBook connecting directly to HDMI Tv input. 
Is that your question?

I stream from Amazon and HBOMAX mostly, i use an HDFURY To convert down to 1080p but it passes the HDR to my PJ.
Apple decodes audio so ur processor/receiver will show multi ch in. Now On the other hand my Denon receiver shows Dolby Atmos, so I guess it pass’s  Dolby Atmos but not Dolby Digital 5.1

Generally for best quality (especially audio) you still need blu rays. There are some fancy specialty download services. But normal streaming from Amazon, Hulu, Netflix is pretty terrible. Apple and Disney are a little better but still way behind the blu ray.  

For surround, I use HDMI from an Ayre DX-5 DSD disc player to a Bryston SP3 processor. I suppose it would be trivial to add HDMI from an Apple or Amazon streamer. Only complication is that I take video straight for the DX-5 DSD to the projector, but Bryston claims to pass video through the SP3 without processing it. And if I do that, I might as well run HDMI from Cox cable through the SP3 as well. The SP3 returns balanced front LR to the Ayre preamp and sends side and rear surround to a pair of NAD amps.