What do you think is the most impressive port? I definitely don't feel it's Fortnite but what else?
Well, Fortnite just got a patch a few days ago and now it runs at a higher resolution, at least subjectively it looks 720p in the portable mode. And it also feels smoother than before the patch. All it's missing is SSR and better AF, and gyro, and it would be mighty impressive.
Another mighty impressive port is Outlast 2, imo. Native 720p in portable, doesn't drop a frame, keeps basically all the visual features... Now obviously DOOM is more demanding than Outlast 2, but the performance differential is small there. And it has essentially the same visual features that id Tech 6 games have.
After the patch, Rocket League is quite amazing too. Similar framerate to the other systems, 900p docked and 720p portable, albeit reduced effects... Which are the ones the pros themselves turn off on PC.
Rime is impressive too. It's a demanding open world game, maybe not the most technically impressive one, but whatever it is it's doing hammers both the CPU and the GPU, and after the latest patch the Switch version is great. It's missing some shadow maps, but it's good stuff, comparatively.