Given the state of all the other port jobs to Switch, this obviously shows that way more work was done beyond just turning settings slightly down, bumping resolution up, adding dynamic resolution scaling, and locking the frame rate to 30fps.
I'm sure we'll hear about this later, but Virtuos probably had to go in and rewrite a substantial amount of this game's code in order to get it to run this well on Switch. I hope we see more ports of this caliber in the future.