I assume you U4K broadcast is really 4K HDR->1080p HDR->1080i->U4K faux HDR. Or some convoluted conversion path like that.
Correct. Note that the middle "1080i" is really 1080i SDR video and AC3 DD5.1 audio, even though the original Olympics OBS sequence did start with camera-native 4K HDR video ...

Why are the replays SDR if they are replay of the live HDR events that were recorded?
NBC wants to force you to watch the ads (or at least not FF through them). Even if you subscribe to their ad-free premium service when you watch anything HDR which they restrict to "live" in order to seduce you ...

In all honesty, there's really nothing to motivate watching the Olympics on NBC broadcast, ATSC 1.0 or 3.0. First of all given the 6-9 hour time zone difference here in the US with rare exception virtually nothing that you see during day or night will be truly "live". Perhaps it might be live ...

Actually watching live using other apps and silicon dust tuners does give you most of the capabilities you are discussing such as REW, FF, Pause etc. I use these all the time while watching live tv and really enjoy it. But these functions are enhanced when viewing a recording. So I don't really ...

The whole point of DRM is prevent recording.

My question is.
What TV content do people record nowadays?
Anything at all that you are unavailable (or prefer not) to watch when it airs. ANYTHING!

That is the entire point of VCR/DVR for personal use... to allow the viewer to record anything when ...

I've been a user of SD products for over 7+ years, and I love them. Not so long for me. I jumped in with the Flex-4K about 1.5 years ago. Loved it, and still love it... for non-DRM ATSC 3.0 here in LA.

I don't use or want a Za$$erbox, but because they are cable to record ATSC 3.0 DRM's content ...

I wouldn't put much stock in their "future plans", given the current restrictions in place.
It's unknown exactly what they are really describing.

But as I interpret things they are not hindered by wanting to stream DRM content around the network to popular player devices which are themselves ...

From the first post in this thread:

Will DRM encrypted ATSC 3.0 channels play on my Android or Fire TV device?
Using a gateway product - we expect it will be possible in the future but it is not possible today. The Google Widevine DRM decryption is possible but there are other requirements that ...

ATSC 3.0 audio is fully supported on Windows with the HDHomeRun app. No codec pack required. Wait... are you referring to the cloud-assisted decoding automatically invoked by the Windows app as what you call "fully supported"?

Windows 10 or Windows 11?

Yes, it does work and produce sound and no ...