Hi coone,
Welcome.
All motors can generate and all generators can motor, if properly excited. Here, "excited" means the type of field winding in the dynamo (which is an electric machine (motor or generator)) and the controller between the dynamo and load and/or source. So, one dynamo can function both as a starter motor and generator for battery charging and auxiliary system power.
But
And yes, this "dynamo" can be made larger and designed differently so it starts the engine, can actually propel the vehicle to some degree and charge the battery, either from the engine power or from regeneration. See the Honda hybrid system for an example.
Pick one
Regards,
major
ps...please call it a motor (or dynamo