If the Switch 2's OS is anything like the Switch's current revision of Horizon, it's an extremely hardened OS. They've done a surprisingly good job plugging software holes.
3DS advertised AR from the get-go, even coming with a set of cards and built-in games to show it off. Never ended up being anything more than a neat tech demo that people forgot about almost immediately. Haven't really seen anything to make me think people are more interested in it now, over a decade later.
VR headsets and the research behind them have made it possible to accurately track the position of the device with very little processing cost from a single camera. Additional cameras are simply for occlusion and field of view at this point. A coupled depth sensor handles any needed resolution of positional conflicts between real world objects and digital objects.
That tech wasn't there for 3DS, even with 2 cameras it wasn't stable or accurate, and it was pretty low res and low angle, and it couldn't tell if the digital content should be occluded by real world objects at it's perceived depth. Plus there are actual AR games now already established, and the framework and proof of concept to easily on-board new ones. Also, by the time the Switch 2 is released, the mainstream AR headsets and content will be even more established. Currently the best AR content is either on expensive headsets or in limited form on iPhones. But in less than a month the Quest 3 is out, an accessible mixed reality headset. It will have been out for a while by the time the switch 2 would come out.
This is very much one of the directions gaming is going. It doesn't have to replace all gaming, and never will. But it will be a pretty big part of gaming. Especially once there is enough public trust behind it for people to play augmented reality games outdoors. Us nerds already do so, we know we won't walk out into traffic even if the headset malfunctions. But the hypothetical "everyman" is apparently worried that they might? That's just not how anything would work... but whatever. It's safer than playing a phone game and wearing headphones, since letting the real world in and paying attention to both is the whole point, sight and sound.
You're absolutely right about VR. But I don't think AR is ever going to be that big. There just isn't as much of a point in mixing the real world with artificial elements. The only reason to do so is to get information that can't be emulated as well for VR. As VR gets better, AR gets more redundant. AR of the style we see on phones (like pokemon go) is even more pointless. AR will stick around for virtual desktops and smart glasses and the like, but for gaming it will always be a gimmick.
The fact that I had to open an app on my phone for voice chat meant that I never ever used voice chat.
I don't really care if the next Nintendo console has a camera. But I extremely do not want to be forced to use some app on my phone to play the game on my Switch.