The electric propulsion systems are well developed; motor and controller.
100 to 600 HP motors are now in production. the EV controllers designs can handle the power needs.
The big problems yet to be solved are the battery energy density, in kWhr per pound.
My Cessna flies at 120 mph on 120 HP. 4+ hours of fuel gets me about 500 miles of range . So, it uses 480 HP- hours. A battery with a capacity of 360 kWhrs would yield the same range.
Today , that battery weighs 3,600 lb. , over 1,000 lb over the allowed gross weight.
So, a battery energy density improvement of of 12 x would have the battery weigh 300 lb, the same as the 50 gallons of av gas, that my Cessna holds, and still allows 570 lb of people.
The other problem is recharging that 360 kWhr battery. Even at 480 volts mains, it would have to source 750 amps to recharge the battery in 1 hour.
That infrastructure is very costly…Who will pay for that at every airport ?
Note that an E-power system like this will require liquid cooling for the motor, controller and battery, as in the Tesla 3…a very complicated cooling system.
So E-power at these power levels are not simple systems.
So, I see long range E-aircraft a long way off…