UHD Rip --> MakeMKV --> Jellyfin --> Roku = CHOKE

[eracer1111]

- UHD (with HDR) ripped with Pioneer BRD-S13UBK seems to work flawlessly.
- MakeMKV using Default profile.) Selecting the main title and all its defaults results in .MKV file in target directory.
- Jellyfin server on Core i7 computer connected (ethernet cable) to same network as ROKU (WiFi).
- Jellyfin app running on Roku.

Playing the video results in Roku choking on playback after about 30 seconds. I see a flash of an error message, but can't read it. I tried multiple UHD titles - same result.
Limiting bitrate in the Jellyfin options to 54 mbps allowed the title to play, but disabled HDR.
55 mbps kept HDR, but Roku choked.
Neither option works for me.

DVD's and Blu-rays using same basic method work fine. It's just UHD discs that are a problem.
I've read through the forum and culled some information that led me to think that high bitrate audio was the cause. This seems confirmed when I used MediaInfo to compare a main title .MKV and a trailer .MKV from the same disc. The trailer had AAC stereo, and played in HDR just fine.

So I ripped a UHD disc and used the MakeMKV 'AAC' profile, and made sure the Lossy Stereo option was selected. The title played without Roku choking on it, and HDR was maintained. So it seems to me that it was indeed the total bitrate with HDR and high bitrate audio that was the culprit.

But the video was in B&W. I don't understand why this happened using the Default profile.

I currently only have a 3.1 ch. audio system (L-R-Center + Sub) but I plan to add two more speakers and will use 5.1 audio. 7.1 is not in my future. So I'd like to store my UHD titles on Jellyfin with the option to select Dolby 5.1 or DTS 5.1 in the future (since my integrated amp supports those formats.) AAC format would be fine.

In short, creating a .MKV title with stereo AAC tracks, additional 5.1 option tracks, and HDR is acceptable. But of course I need the video to be in color.
I'm testing the FLAC profile now.

I know I can use one of these two options to solve the problem as well:

1. Re-encode using Handbrake (takes extra time.)
2. Purchase and use a Ugoos AM8+ (extra $$$.)

I would prefer to playback .MKV files of my UHD discs from my Jellyfin server using the Roku app, and have HDR and 5.1 audio options - all without spending more time or money. Using the AAC profile is fine - if I can get color video playback.

I'm comfortable editing .XML files and can follow the advice I've seen in the forum for creating a new profile for use in MakeMKV.
But the AAC profile shouldn't need editing to give me color playback, should it?
(I did deselect all subtitles when I made the .MKV file using the AAC profile. But that couldn't be the reason for the B&W playback, could it?)

All ideas are welcome.