NEMA17:
Steppers with fewer steps should be faster and/or cheaper.
I don't know that the first would be true and the second depends on production volume, not the number of steps.
So.. at what voltage should I run the above stepper to get the maximum out of it? And which TB65xx chip would be suitable for the stepper?
That's a bit like "how long is a piece of string".
I don't know which chip you should get - my suggestion is to look for a stepper driver board that uses one of those chips and then consider the current it is capable of providing. Or, more generally, search for a stepper driver that can handle 3 amps or 4 amps or 5 amps.
The maximum voltage will generally be determined by the limitations of the stepper driver. But you may not need to go to a really high voltage to get the performance you need. Experiments using the motor in its working configuration are essential.
...R