Yes, sadly both Switch 1 and Switch 2 carts are flash memory. It was the same with the 3DS too, which is already starting to have a handful of games degrade and have issues or outright stop working.

While this is not yet the case for the Switch 2, the Switch 1 can be homebrewed and then used to rip your own offline digital backup copies of your cartridges. You can then continue to play the physical cartridges until they eventually stop working 15-20 years from now (or from whenever that copy was manufactured)

On the 3DS, there's actually a way to 'charge' the games with a feature that comes with Godmode9 which is automatically installed only when you homebrew the console. It doesn't make 3DS carts live forever, but it does SIGNIFICANTLY increase it's lifespan if you give them a charge once every few years or less. If you have a 3DS, I recommend doing this, as even the cartridges that seem to work fine often have already degraded a bit, and charging a working cart is still just as good.

Maybe you don't care about 3DS, but I just wanted to point that out since I'm hoping that someone develops their own equivalent version of this cartridge charging solution for Switch 1 games, and eventually Switch 2 when that gets successfully hacked, too.

I'm not sure about the exact type but no, afaik there's no battery or anything inside. However, sadly, almost anything can and will degrade and we don't yet exactly know when that will be.

But honestly, I've got quite a few old modules around me (eg gb gg lynx pce - though not collections per se mind you) and some of these have seen really rough days but all of them still work fine. So it might not be relevant to our lifespan and easier to put out of our mind, but still it could surprisingly happen. Working in IT though being certain to maintain data is not a trivial matter of redundancy and moving.

Anyhow. Switch 2 games afaik are more akin to ssd because it has to be streaming data at a far quicker pace to the ram, like mkw or cyberpunk. So in a technical sense I would say the risen price is generally worth it. Switch 1 modules are more like slow mass storage (eg SD, the slow ones, explicitly not EX SD).

But back to the point, none of these need "charging" in that sense (but still degrade).

Game Key Cards don't exist on Switch 1, those are all full cartridges.