Looks like a MBR0520L to me.

There should be two 1/2 ohm resistors there, they always burn out, just like they did on mine, just poor design. Replace them with half watt resistors...

Possibly these?

I'll see if mine is the same when I'm in work tomorrow. Take note, the resistor in that pic (marked R050) and the rest of them on the board with the s...

I've had this and factory resetting the switch cured it, as has opening the joycon and temporarily disconnecting the batt.

No, they are aerial plugs / interrupts. They are used during manufacture to temporarily connect RF test equipment to measure / calibrate RF.