Where are the exact differences?
Can you play all games, even on the go? Could you log into a hotspot for online games?
I know that the difference between the Switch and the Switch Lite is that the Switch Lite can't be connected to the TV and multiplayer does not work either because you can't disconnect the controller, like with the Switch?
There are also differences in performance, the Lite is the slimmed-down version
Where are the exact differences?
https://www.nintendo.com/...h/compare/
Can you play all games, even on the go?
Yes. For some, however, additional controllers are required
Could you log into a hotspot for online games?
Theoretically yes. I don't know if the switch supports login portals though - iirc no
And multiplayer doesn't work either, because you can't take off the controller, like with the switch?
Local multiplayer works - you can buy additional controllers and connect them wirelessly.
Exactly
It's best to get the Lite only if you are sure you don't want to use it on the television. It is also better suited for gaming on the go, as it is smaller and lighter. And the Lite is cheaper too.
You can play all games, but for some like 1-2-Switch or Ring Fit Adventure you need a controller.
You can of course log in to Wi-Fi hotspots, but for online games you need an online subscription for both consoles, namely Nintendo Switch Online. For local multiplayer you either need Joy-cons or another console, depending on the game, so you have to look in the description of the game.
However, the Lite is slightly smaller than the Switch, and the Lite has a better battery, so you can play another half an hour longer.
My opinion:
Only buy the Lite if you really don't want to play on TV, otherwise the price difference is too low for the missing features, listed again:
No detachable controller
No possibility to use TV / screen
No HD rumble
I would of course be happy about a star, if you don't want to give it to me, give it to xxxcyberxxx, whose answer is also very good.