Modern automatic transmissions in ICE vehicles are able to achieve better fuel economy than the manual version of the same car. Modern autos have 7+ gears and can spend more time at the optimal throttle and engine load to maximize efficiency. They also lockup in nearly every gear rather than just relying on a fluid coupling.

I'm not surprised Jeep is thinking of releasing an EV with all their legacy mechanical drivetrain, but it's going to get horrific range. The losses from going through the transmission, transfer case, drive shafts, and differentials is pretty high. It also doesn't help Wranglers make bricks look aerodynamic. The PHEV Wrangler uses 428 wh/km in highway range tests and this would likely be a little worse. The manual will have a little less loss than the auto of the PHEV, but the extra weight in batteries would probably more than offset that. For comparison, my Model 3 SR+ consumes about 150 wh/km at highway speeds. That's one of the most efficient EVs available, but even the wave of electric crossovers that have been hitting the market recently are in the low 200s wh/km.