So... Its a good console, because with a switch, you have the risk of getting online banned and stuff
While I never owned a Switch, it looks like it is possible to avoid bans as long as you're careful to segregate your activity between emuNAND and sysNAND. As far as I gathered, as long as you don't cheat or load backups on sysNAND, you're free to do whatever you like on emuNAND and you won't get banned.
If you just want to emulate other consoles, there are other devices that are vastly superior at this point. They're probably much, much easier to set up, too. Perhaps a Steam Deck would interest you?
I'd argue that setting up emulation on a 3DS is actually easier, provided the system has already been modded. Furthermore, the Deck is a lot less portable... as much as I'd like to defend it, the difference between a backpack and a pocket is massive.
Something others didn't seem to bring up is that playing DS/3DS on a phone, or worse, a single-screen handheld, is a vastly inferior experience in many cases. On a phone, there are no physical buttons, and on a handheld, you're stuck with two screens laid out horizontally. If you can put up with that, sure, but I wouldn't recommend it, especially for the more awkward touchscreen controls.
Additionally, capacitive screens require less precise or much bulkier styluses, and low quality touchscreens are a terrible match for any stylus. Since nothing uses resistive touchscreens nowadays, that would be a problem for games where using the finger is significantly worse than a stylus.
but if you don't want to play in 3D, is a worthless invertion
Absolutely disagree. A lot of people just kept the slider down at all times. As pointed out above, there are benefits beyond just the 3D screen, although it is definitely one of its selling points.