exactly - Hydrogen fuel cells even as range extenders but better yet as primary power source (small battery for starting power and other benefits). It is only a power source nothing else in the powertrain changes
but that won't be until 2030 in my book for sedans and different material batteries may be viable by then
the Robotaxi though should be hydrogen from the start - cannot be parked charging when you could begetting revenues. A few H2 Taxi fleets in Europe already proving the point