Source?
https://cleantechnica.com/2020/02/19/bloombergnef-lithium-io...
A source on electric motor efficiency: https://insideevs.com/news/348504/tesla-improves-motor-effic...
A source on internal combustion engine efficiency: https://en.wikipedia.org/wiki/Engine_efficiency#Internal_com...
As to the drivetrain losses through transmissions and differentials, I have only my own experience from working on cars, dynos (measuring the power to the wheels), and racing. It depends on drivetrain layout. front engine front wheel drive has fewer losses than front engine rear wheel drive, all wheel drive usually worst of all. You lose another 5-15% depending.
Probably you will also find this video interesting, which goes into depth on the full lifecycle of different fuels and the overall efficiencies:
A gas car getting 26 mpg -> 26 miles from 33.41 kWh of energy -> 1285 Wh/mi
A Tesla Model 3 getting 353 miles from a 75 kWh battery -> 212 Wh/mi
That's a 6x advantage.