Match resolution to output 1080p instead of 4K

Just got Channels DVR today for the World Cup game and was surprised that with my ATV setting of match content, Channels output a 4K signal from HDHR Fox -> ATV -> Projector. I use 4K60 SDR as ATV's default resolution for smooth menus etc., but with match content, other sources besides Channels deliver only HD resolution when the source material isn't 4K. The reason I (often) prefer HD over UHD for broadcast material is my projector does not allow frame interpolation with 4K input, which I prefer for sports. Am I missing a setting?

Our entire app runs in the native tvOS resolution, and our player currently doesn't do any resolution matching.

No one has noticed or complained before, but I can see how this can be an issue with your particular projector.

Interesting, thanks. I've been reading about how ATV4K has no "resolution matching" settings. But I can confirm that some ATV4K apps do preserve HD from source to output, so there must be a way.

That's something you'd have to implement in Channels to avoid ATV auto-upscaling? If it's a straightforward addition, it would be very useful to me so I could use frame interpolation on broadcast HD sources. I can always switch the ATV's native resolution, but then again I subscribe to 4K Netflix for a reason...

What apps are you using that will pass a 1080p signal when the ATV is set to 4k?

I've tried to confirm this but have been unable to. So it's possible I was misremembering a resolution change for non-UHD source material in some apps like Prime Video. So perhaps this goes in the "general ATV annoyance" category.