Switch 2 version is now online here.
Did one fight in my old savegame and compared a bit with XBC1 in handheld mode. 60fps seem super stable so far, not one drop in my short test, seems definitely more stable than XBC1.
Handheld resolution is unfortunately not as high as in XBC1. It is not terrible, but it is a little bit lower, not much, but a little bit. Giving that XBC1 wasn't native res either but a very very good upscale, 1 feels like somewhere in the 900p while this feels like it's scratching on the 720p with upscaling (not sure if same technique as in 1). If you look at your main characters face and zoom in a bit you can definitely see the softness that other lower res Switch games have, but it's still pretty good looking, just not as good as XBC1 when it comes to clarity but also not as bad as "Ewww, this is not native res, I rather don't want to play now" there are other games where not being native res look definitely way worse, even tho they might be similar resolution, so it's still good news. No idea if there is still dynamic res and it could drop further tho.... Will test docked tomorrow.
Menus and UI and everything all native 1080p like in XBC1.
Patch for the Standalone Add-on (I have it physical) is still not online tho.