I think my Nintendo Switch took a bump when I was carrying it with me into bed last night (don't at me) because it suddenly said the MicroSD Card had been removed while it was still inserted. So now despite formatting the card the Switch still won't detect it, and I guess my MicroSD-port is faulty. I'm picking up a cheap MicroSD card today just to see if it can detect it, but my hopes are low.
If the slot is broken, I just don't know if I can be bothered with sending it to Nintendo for a repair? It's convenient having the extra storage, but hardly essential, especially if a Switch Pro of some sort is coming.