>>718393051 (OP)
Yes and no. I'll break it down by mode
>TV mode
If the internal resolution of the game is 1080p, the Switch 2 only goes that far. If the game uses adaptive/dynamic res, it will stay in 1080p on Switch 2. When a game uses variable resolution if the framerate can't maintain 30/60FPS, the resolution drops to accommodate it. But when Switch 2 horsepower kicks in, the dynamic res won't drop.
>Portable mode
The Switch 1 resolution was 720p, whereas the Switch 2 is 1080p. If a Switch 1 game runs at 720p native, the Switch 2 stretches it to fit its 1080p screen. If the game is 540p native, it will stretch to 1080p. Think about it this way, blow up an NES/SNES game that was 240p onto a 4K TV and hit Fullscreen mode in one of the options. That's what's happening in portable play. Going from 720p to 1080p in the Switch 2 screen is fine, but lower than that and it's gonna be a problem without a patch.
>>718393485
A Switch 2 Lite that's portable only would probably be 350 dollars. They may or may not drop the 120hz screen.