Viewing on Channels at home means no transcoding. I believe when your viewing on TVIMate, you are viewing transcoded signals. Did you try increasing the playback quality under advance tab to see if that closed the gap between Channels and TVIMate picture quality?
EDIT Maybe it doesn't transcore? I tested using xTeve to push into Plex and not seeing a chance in PQ when adjusting the transcoding settings on the CDVR server.
I'm not even sure at this point. TiviMate had some appealing features, but ultimately the UI was too janky for my liking, and I haven't picked it up in a couple months. If I get brave, I'll dig back in and check out the playback quality in the advanced tab.
I recently discovered another entrant in the multiview-capable app space, at least on AppleTV:
I've been playing around with it for a bit on tvOS and iPad and it's pretty nice. It accepted the M3U and EPG I copied out from Channels. Overall it feels a bit better than Tivimate. The app's UI needs some work but it's off to a solid start and the updates have been frequent. Hopefully it keeps getting better.
What are you using for M3U/EPG? The same URLs from iprotv get me UHF's (somewhat childish) "no playlist, seriously?" prompt. 
Here's the format I used that works with the UHF app. I copied the URLs from Channels DVR and edited the first section to be the internal IP address of my CDVR server, made it http:// instead of https://, and removed the "?format=ts&codec=copy" bit at the end:
M3U:
http://CHANNELS-DVR-IP-ADDRESS:8089/devices/M3U-SOURCE-NAME/channels.m3u
EPG:
http://CHANNELS-DVR-IP-ADDRESS:8089/devices/M3U-SOURCE-NAME/guide/xmltv?duration=1209600
The "duration" part in the EPG URL isn't necessary, it works without it too:
http://CHANNELS-DVR-IP-ADDRESS:8089/devices/M3U-SOURCE-NAME/guide/xmltv
1209600 seconds works out to be two weeks of guide data. So if you're just using UHF for live multiview, and only need 6 or so hours of guide data, it may make sense to use something like 21600 instead.
OK - it didn't like any switches at end of M3U - that explains it. Thanks.
My kingdom for a client that:
Exposes channel ID's
Allows interactive building on tvOS
Uses native sound (including AC4 thanks to stupid ATSC3)
I'll play with this one, but my suspicion is that I'll be back on iProTV soon enough.
Yep. Took all of about a minute to disqualify this one.
I started an OTA stream with 5.1 audio.
Next started ESPN TVE with stereo.
Whole mix of channels got down mixed to stereo channels only. 5.1 channel only got FR and FL.
The interactive build of the multiview is pretty good though.
Anyone else playing around with "Multiview" apps may be interested in this new feature in the latest Pre-Release of Channels DVR:
In my setup, it makes more sense to be able to share M3U's from customized Channel Collections, than it does from entire Sources.
I tested by exporting my own "Favorites" M3U into UHF using the URL syntax above, and it's working fine.
This too:
I will say for UHF - they are clearly actively developing! I'm going to raise my bug + feature req, and see what happens.
The search for the Holy Grail continues but in the meantime I've discovered another contender for "Best Multiview Client of 2025" and its name is "Snappier IPTV."
Took me just a couple of minutes to get the hang of it, but I'm already liking it more than UHF for this purpose. Note that the free version is basically a demo, the stream stops after 4 minutes. But payment also unlocks multiview, which this app calls “Multi Screen.”
The cost is $50 for lifetime, $20 annual, $10 for 6 months, or $2 for one month. I sprung for a month and I've played around with it for a few hours now. The interface is bare-bones, but it works well. It covers the bases, offers some new ideas and energy and the overall UI feels reliable and snappy™.
It's pretty easy to configure too, all things considered. I'm impressed and going to stick with it for a few months. The app works pretty well right out of the gate on AppleTV 4K, and not-too-badly on macOS too, for Macs running Apple Silicon.
If anyone else checks it out too, I'm curious to hear what you think.
Since I'm a glutton for punishment here - I'll take a look this weekend.
Al Pacino in Godfather 3 - that's me. 
I signed up on their Discord channel and see Snappier's roadmap, which is encouraging:
This is the current roadmap for Snappier in 2025 and beyond.
This is not in any particular order and some items may never be added.
The roadmap is evolving and a work in progress.
- Profiles for Multi Screen (Save current setup to a profile name like Football and have it auto restore)
- 1 large and 1 smaller window for multiscreen with option to flip between the 2.
- User Profiles.
- Add items to custom categories by long pressing on them.
- Better category/channel changer UI when swiping down on live tv.
- Channel/Category selector for importing.
- M3U Mapper. (So all M3U files should work)
- Create own 24/7 channels for tv series.
- Movie Collections. (Show other movies in a movie collection - for example “Terminator” will show all the terminator movies)
- Realtime Sports schedules.
- List view screen for live tv, make it expand the small video window to large rather than stopping and starting.
- Scraping of TMDB metadata for better app functionality.
- Download tv series for offline viewing. (iOS/iPadOS only)
- Recording Live TV (KSPlayer and VLC) (iOS/iPadOS only)
Snappier can also launch directly from Channels via this URL: snappier://
(from tvOS, at least)
So I've added a "MultiScreen" button to the interface in one of Channels' Personal Sections, with a matching icon, thanks to this new feature:
App performance for me, on a large EPG, is easily the worst I’ve tried. I’ll try it with a tailored collection, but not promising so far.
Hmm, I only fed it a curated Channel Collection of about 25 channels, since all I use this app for is MultiScreen, anyway. Performance and overall UI is very snappy for me, certainly compared to the previous 5 multiview apps I’ve tried over the years. At least on a 4K AppleTV...
Fellow multiview fans will appreciate the interface on the F1 app:
It sounds like it still won’t be fully customizable but expanding the feature is appreciated nonetheless:
Still. One day, it will happen
For those interested in more CDVR-based multiview solutions, these are some excellent new developments:
I've Dockerized Multichannel View for those with amd64 processors. Tested and working nicely with Intel Quicksync. I'll add it to Project One-Click soon: