You can’t get 6 kW from charging via 120 volt.
You have changed your display from miles to battery percentage. You were previously getting 6 MPH charging, which equals about 1 kW. Same super slow charging rate, just displayed differently.
As noted above, with 120 volt charging it can heat the battery or charge it, but not both at the same time. If it is below freezing for an extended period of time while plugged into 120 volt, you may see the battery state-of-charge decrease as it is not able to keep the battery warm enough to allow charging.