If you’re a tinkerer / interested in emulation a nice Samsung or name brand USBC thumb drive for moving files. I found this to be the accessory I needed the most and which saved me the most headache once acquired.
I almost always play in handheld mode. I did ultimately buy a cheap USBC dock so I could watch movies / have on the hotel tv while traveling.
I got one of those mounts which latches onto the deck. It sits on the wall now beside my couch. I like that, personally.