Don't all 4K TV have some sort of HDR? So if ur asking whether to stay with 1080 for now, I say maybe YES.
Just got my first 4K with and I must say even 720/1080 look more realistic because of the increased brightness and FALD, mine hits 1,000 nits and I will say don't bother with brightness less than that. So HDR is only half of the story.