PSNR is a terrible way to measure video quality. SSIM is better but not great. VMAF is good but it’s skewed towards the types of material netflix has.
Objective video quality is a tricky thing to do and you can easily come out with a codec that’s great at fine details in foreground people but terrible at high speed panning of water and trees. Depending on the material depends where you want the quality to go.
For comparison, HEVC claimed 50 to 60% compared to AVC. You can compare with reality...