I'd try to have spare Uconnect, PCM, throttle body, supercharger, bcm, security gateway, and any sensors you can easily find. Maybe injectors too. Think about stuff you likely couldn't get from the local parts store.
Having said that, I will say my 23 year old 4Runner wasn't too bad to get parts for when I started restoring it a couple years ago. A few things were discontinued like interior panels and stuff like that which was a surprise. Body clips, bolts, hoses, etc were all available and reasonably priced.
There may be a slump in availability while parts are unavailable from the dealer but the aftermarket hasn't picked up on them yet. I thought there was some regulation that required a manufacturer to have parts available for a certain amount of time, but I'm sure Stellangtis will try to weasel any way they can to cut a corner.