You’re likely going to be waiting a while for the grid heater relay. 2021’s aren’t slated to be able to get the fix until mid May. My 2022 still hasn’t been fixed, and the dealer still can’t get parts for it.
As for the transmissions, I’m not sure how it works with cab and chassis trucks that are already being upfitted by an RV manufacturer, however inwas told by a dealer that Ram released a revision for TSB 21-002-23 back on March 8th. This revision included an upgrade to an “RSU” (Rapid Service Update). As part of RSU 23-065, dealers were supposedly able to look up VIN numbers for un-sold units that are affected by the TSB and the k1 issue. From what they said, Ram was urging dealers to look up the vins for unsold trucks through DealerCONNECT and then subsequently install the parts from the TSB as a preemptive fix. Not sure how accurate that is, but it would be worth investigating.