Switch (docked mode) – 1080p / 30 frames per second target
Switch (handheld mode) – 720p / 30 frames per second target
As for MGS1:
“arrives virtually unchanged, as this is an emulated version of the 1998 game, lacking widescreen display or up-ressing, which may come as a disappointment for players hoping to play MGS1 on their 4K TVs”.
Yes, the PS3 ran this at 720/60. So the switch doing 1080/30 docked seems about right.