My TV and PS4 Pro have HDR. I'm sure it helps make brightness better, but it just makes everything look yellow.
Also, I don't even think my TV's HDR works with its apps. I distinctly remember House of the Dragon and trying to see something. I accidentally closed the app and reopened and suddenly it was super clear. It's like it turned the HDR on (or off) and suddenly everything was visible in an otherwise dark scene.