Aside from size, steppers can have varying characteristics within a given size.
Choosing a size is just one of the things you have to do.
This is were I usually get my steppers:
https://www.omc-stepperonline.com/nema-23-stepper-motor
Their selection of 24s is slimmer:
https://www.omc-stepperonline.com/nema-24-stepper-motor
Here is some guidelines on choosing steppers:
https://docs.duet3d.com/User_manual/Connecting_hardware/Motors_choosing
Frederick