Put a friggin trailer hitch on the dammed electric car so it can tow a compact trailer with a diesel fuel tank and a generator that can also supplement the heating and air conditioning, plus extending the mileage.
I could design one with a live axel that gives extra pushing and dynamic braking.
Kinda like a diesel electric freight train helper engine.
The setup you’re describing reminds me of the “slug” on railroads, which is a diesel-electric locomotive with the diesel “prime mover” removed and its traction motors powered by another diesel-electric coupled on. Railroads use them as boosters for extra traction at low speed, and sometimes as fuel tenders to extend range.