I picked up a Samsung KU6290 55" Refurbished from BJs for $400 shipped, this is for the living room.
The tv looks new, minus some small scratches on the back and fingerprints.
It's not "Real" HDR but it looks good, smart apps work really well too. Pictures quality is much better than the 2003 Sony XBR Projector it replaces LOL
I'll probably pick up a good 43" set for my bedroom, I'm thinking maybe the Sony X800 if it's on sale or a comparable Vizio...
Yeah this is the way to go.
OP nobody is saying you have to buy the cheapest 4k HDR you can find at the grocery store, also you don't need to have the top of the line for $1000+ if you're not comfortable with that.
There are excellent midrange options as quoted above; they are often missing enthusiast features like 10-bit panel, wide color gamut, dolby atmos compatbility. BUT you still get a 4k image, especially if the TV has a great upscaler and high contrast capability. Depending on the TV, HDR can have input lag, which may be a dealbreaker if you're a competitive gamer. I've seen HDR implemented well and poorly, side by side comparison of simulated HDR, 8-bit HDR, and true 10-bit wide color HDR.
Set yourself a baseline of features and go from there. The Sony quoted above, Vizio M, Vizio P (on sale), Samsung 6000-series, all fine choices.
EDIT: I totally missed that you had your eye on the KU6500! Cool, I have that TV, almost 6 months now, it's really nice. The $600 saved on the next model up went into a PS4 Pro