UPDATE: Rivian contacted InsideEVs to provide some clarifying context regarding the registration status of R1T vehicles in New York.
"It is not necessary to register an R1T or R1S as a commercial vehicle in New York, and they should be registered as passenger vehicles unless they are intended for business use. There was a period early on where this was not the case, but evolutions in the state's policy mean R1T/S owners can and should register their personal vehicles as personal vehicles."