I dont think there is a single title which is the best because different games do different things better and worse.
But here are some games I think offer the best visuals.
RDR2 is still such a polished and deatailed experience on a decent PC its still on of the best looking games. Flight sim has some of the best clouds + cloud lighting
FH5 has some of the best foiliage and environmental detail.
Another great shot from RDR2
RETURNAL is impressive smoke effect which looks relistic, I think its a fluid simulation. Combined with there particle systems its a visual feast @ 60fps.
Some more rdr2
The man of median has some crazy character models.
More flight sim
Not the best image but TLOU1 remake, naughty dog are really pushing the detail level in the environments.
Rift apart has ut all, amazing particles, rt reflections, high geometry, great lighting and at 69fps.
Horizon forbidden west has the best looking in game chracter to model ive seen to date, it does not lose detail abd look lower poly jank like a lot of games do. The environment are impressive too. All at a sexy 60fps.