I don't think it is wrong to say that the best-looking 3DS games if remastered (given higher-res textures and a resolution bump) would look similar to Sword and Shield.
Monster Hunter Generations Ultimate has better animation work, and roughly comparable visual quality to Sword and Shield. Both games incorporate fixed cameras in their perspective, so world design is very similar. 
Of course if you're going to compare a Game Freak game to its predecessor it will look better. But Game Freak's 3DS efforts were lazy as well. The 3DS isn't that much less powerful than the GameCube yet the Pokemon games looked far worse than their GameCube peers.
Now compare these efforts to something tailored for the Switch and has high quality assets like Monster Hunter Rise.
