Re HLG, I think one of its selling points vs HDR 10 is that an HLG stream can be backwards compatible with non HDR TVs. So maybe, my TV is on the list because it has implemented the backwards compatibility mode of HLG, and just displaying basic UHD but no HDR? Hard to say really, without a side-by-side comparison of two identical sets, but it certainly looked as good as anything I've seen on that TV.
Trouble with Netflix is, last time I looked, their 4k content seemed to focus on the home-brewed material, none of which I have ever liked much. Not saying it's bad for everybody, just that I personally don't like their style.
Amazon too, have some stuff in 4k, maybe I should look again, but nothing so far that I wanted to watch. Mine's an Apple household so I could be tempted to invest in the new 4k Apple TV but even then, the reason I resorted to iPlayer last night was that I'd had a nice dinner and a glass (or more) of wine, was in a mood for TV, and would have been happy to pay for an Apple rental. And then I spent ages browsing both Apple and Netflix, and failing to find anything new that caught my interest.
I guess it could be argued, I'm getting too fussy.