I agree with Efrain, I don't see a need for a high-end i9 or i7 in a HTPC. Since you're just after the integrated GPU, I would look down the product stack for a lower-end CPU with the same graphics. Additionally, the 11700 has recently been panned as a "waste of sand", and the 11900 as "a waste of sand trapped in your swimwear".
I don't believe i3's have been released yet, so an i5 is the lowest you can go. Checking on
Wikipedia's Rocket Lake page, I see that the 11th gen i5's come with either an UHD 750, or a lower-end UHD 730. I agree with you that the UHD 750 is the better choice.
For the CPU's that have the UHD 750, they all have identical GPU clock rates as long as you avoid the 11500T, which is a thermally constrained "T" version with lower speeds.
That leaves the i5-11500, i5-11600T, i5-11600, and i5-11600K. The price spread across these three models is only $70, so I don't think that's an important factor. Instead, I would expect design-power to be your main consideration. The i5-11600K is a 125 watt CPU. The 11th gen CPU's are running hot, and Intel is famous for their TDP ratings to be very conservative, so that 125W CPU might end up producing 180-250 watts of heat. That seems like a lot for a HTPC.
On the other end of the spectrum, the i5-11600T is a miserly 35W CPU. While this would work great in a HTPC chassis, you give up a lot in clock speeds. Additionally, even though the UHD 750 GPU is still rated at 1.3GHz, this is a max clock rate and it is not a guaranteed constant-load speed. I fear that running it hard for 4K processing might cause it to clock-down to stay within the 35w design envelope.
Which in my mind leaves two solid choices, the i5-11500 at $192 (in stock on Amazon and Newegg for $218), and the i5-11600 at $213 (not showing in stock on Amazon or Newegg). On average, the 11500 gives up 100 MHz in CPU speed to the 11600, a difference small you might not even notice. Even though both are rated at 65W, I would expect the 11500 to run slightly cooler due to the lower clocks, and that might even leave a little thermal headroom for the GPU to perform better than on the 11600, though again I doubt you would notice the difference.
Based upon all of that, my recommendation is the i5-11500.