PS5 will objectively not look worse than Stadia. Even if PS5 has less than 10.4tf (unlikely), due to the uncompressed image PS5 will look far better regardless. Especially on a 4K screen.
Even a 1080p high bit-rate image (or lossless in the case of native console) looks better and more detailed than a 4k low bit-rate image in every circumstance except when the image is stationary. And it's not like there's time for multi-pass video encoding when latency is having to be kept to a minimum. It's be encoding at the fastest, lowest quality setting.
Nah. Crispness and how clean the image is has to be very low on the scale of perception on how good a game looks overall.
You know what looks better than the highest end 4K 120hz assassins creed (or whatever) on a high end gaming PC? An random episode of anything (let's say...The Good Place) at 720p on Netflix, even with all its compression artifacts, and lower resolution. Hell, rip it to YouTube, double those artifacts and it will still look "better".
It looks real, and doesn't look like video game, and all the resolution and uncompressed textures you throw at Assasins Creed, doesn't make this any less true.
But the same can be applied to video games.
The best looking games are not the ones you can run at the highest settings with the least texture compression. Something like Last of us 2, even at low resolution will always look better than most other current games because it has the best rendering tech and animations. You can't counter that with crispness and texture compression, all that stuff is ancillary and less important to the overall visual impact a game has.