Some e-bike makers offer accelerator/gas functions for their models.
Here is an offer of ekolo.cz e-bikes which you can ride even without pedalling, using a gas lever or a push button on the handlebars. How does battery assist work without pedalling? The ECU is coupled with a speed controller that allows you to ride without pedalling.
The aforementioned gearbox can be retrofitted upon the customer's request with the 'gas' or 'accelerator' function so that it can be driven without pedalling. We consider this adjustment an optional accessory and install it for an additional charge of € 20.