Well after trying both the Switch 1 and Switch 2 demos, I think I'll be safe with getting the Switch 1 version to avoid the game key card. I could not spot a difference at all early in the game between the 2 version. MAYBE a higher framerate on Switch 2, but couldn't tell. I'm honestly surprised how little the difference is. I thought maybe they'd be a noticeable bump in resolution and image quality, or high quality looking textures or even noticeable bump in framerate on Switch 2, but could not spot a difference even when snapping screenshots and videos to compare.
Kinda surprising because even with the Dragon Quest HD-2D, I could notice the bump in framerate at least.