The Marantz Cinema 70s does have more functions than is necessary for you and is an AVR but it was the closest thing I could think of at the time concerning your need for small form factor, 7.1 analog outputs and eARC support.
Now, the Emotiva BasX MC1 looks to be right up your alley. It is an AVP, like your UMC-1, it supports eARC and has a whopping 13.2 pre outs. It has a very slim form factor as well.
I'm not sure of your Roku model, but I have a Roku Ultra that was at one time connected directly to my LG C1. Using HDMI-CEC, one touch of the Roku Home button on the remote controller would power ON my TV and AVR and the volume buttons would adjust the volume on my AVR.
While the Marantz and the Emotiva both process both Dolby and DTS signals, the LG CX and C1 models cannot actually output DTS bitstreams. They will convert incoming DTS signals to multichannel PCM and output them as such when using eARC. Nothing is actually lost here except in the case of DTS:X tracks as the metadata will not come along for the ride after the conversion to PCM. The CX and C1 support Dolby MAT so any devices that output Dolby Atmos using Dolby MAT(LCPM with Atmos metadata) rather than bitstream it will have the metadata intact at the receiving end for proper processing of it.
OK. now we're getting somewhere...
I guess I ought to stop playing records for a bit and play a little more with the Emo...
Yes, we have the Roku Ultras at home. I got them hooked up directly to the TVs via an HDMI connection... they work quite well.. remote is nice. BTW, as an interesting aside, I had some pretty good HDMI cables, labeled '4K' and rather well built, but they were "bursty" when I first hooked up the Roku to the main TV. I had to dig further in the "video cables" box and fished out an 8K cable and that one worked fine. Oddly enough, that first 4K HDMI cable worked fine in my "8K" KVM switch driving a 3440x1440 display... I guess it must have been the inability to drive bidirectional signals? So, computer HDMI cables are not the same as TV HDMI cables anymore?
Now then, the CX and C1 won't export DTS but will export them as multichannel over PCM. Do you mean that I can hook up the PCM over a bitstream digital interface, instead of HDMI, and extract the signal without requiring a DTS license? Meaning the DTS decoding is done in the TV?
Atmos is not important for me, so I don't much care for it right now.
Now, DD, the CX and C1 output the bitstream for down stream decoding?
It sort of sucks... I want the decoding done in one place...
It just might be that either I spend 200 bucks to fix the 12V trigger in the Emo UMC1, get the used Emo XMC1 ( wanting $500, I would offer $389, it's local ) or just tell the wife to get up press this button.
Oh, another question.... or two...
I got two Plex servers with lots of videos and movies. I got them by ripping DVDs and then processing them with Handbrake into mp4. The ripped DVDs are in essence copies and I play them with VLAN... they contain ALL of the surround tracks at native bit rates.
The mp4s with Handbrake also were encoded with all surround tracks at native rates. BUT, I have never tried that experiment of running the Plex client to see if it contains the surround tracks. Mostly because the movies I want to watch in surround in the network can be accessed directly with the computers with NFS and their attached audio decoders provide the audio signal.
When I connect the Emo to the TV and play that audio source, I have noted that Fox Sports comes out on surround... nice... but I have not tried to see if there is surround track on Netflix, Amazon Prime, etc... or even if I run the Plex servers themselves.
What kind of surround tracks should I expect on the likes of Netflix? I guess I should expect the Plex server to also output a 7.1 surround track at high bit rates since that's what I specified when I transcoded the signal.
Thanks.
All of that work, and when it's all said and done, when I sit down to watch TV my wife is watching all of those fire/cop/medic dramas... and then she gets into the Korean soap operas... I fall asleep. Or if I get to watch TV upstairs ( LG 55CX with Roku ) I just tuned to Discovery+ and watch Documentaries or
Airplanes Of The Ancient Aliens.. )...