I bit hard to say since i usually consider other factors when checking out a games visuals.
I guess i'll give the cake to RDR2. Game looks fantastic and has an absurd amount of details, all while being open world with dynamic weather and time of day.
Other contender would be Flight simulator 2020, but only if you take into consideration the scale of the game
But for a personal favorite, i'd go with No Man's Sky. Not only do i like space settings but the game also has pretty much an unlimited amount of landscapes of many different types. Its the only game where i actually spend time taking screenshots.