Very little content available via streaming services is actually in 4K, much less 4K HDR. And when it is available, the content maker might not have done a good job of creating it. The guy who originally posted he could not tell the difference might be thinking he is watching 4K HDR even though most of what he is likely watching isn't HDR, and most of it isn't even 4K. Just because one has a 4K HDR capable TV doesn't mean that everything gets magically converted to 4K HDR, but some people are under that incorrect assumption. Such is the power of marketing! Most content on streaming services is still HD SDR. A 4K HDR TV can't magically make HD SDR content look like 4K HDR.
Nah, there's plenty of 4K HDR content.
Here's Netflix's list: