You should probably get a big ass micro SD card since they are pretty cheap these days. Not sure size limit since don't have a switch. Also if you are going to play mainly docked then you prob should get pro controller.
in terms of size limits I believe the Switch has a limit of 3TB micro SD card, but since the 1TB type of them has just launched this year and that costs 400 sterling, it will be a while before we are worrying about the Switches upper limits on SD card compatibility.
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