I think you’re confusing rec709 with the film look you hold so dear. There are plenty of so-called grungy looking HDR movies on Netflix.
rec709 is a twenty year-old standard for HD televisions that has got nothing whatever to do with the cinematic look. Having more than six stops of dynamic range and greater color space does not instantly transform everything into garish cartoon colors. Chef’s Table is just one example.
And making judgements about HDR based solely on your smartphone is little different from determining the image quality of an Arri while viewing it on a 4”’ iPod. You can get a soft, diffused, painterly image in HDR, just as you can get a brittle, mushy image in SDR.
I will bet you a plane ticket to Vietnam that if I show you two movies side-by-side on my LG OLED, that you will no longer think the same way.
Incidentally, the Pocket 4K shoots HDR, just as the original Pocket does.
Finally, with rec709, you are confined to six or seven stops of DR; with HDR, it’s completely up to you how much dynamic range, or contrast, you want to deliver. That’s what all those little curves, wheels and sliders are for.