I doubt that motor will give half the holding torque while running at 1500 RPM, and saying max speed is 3000 RPM, is very misleading.
Torque curves are available, and all you need to do is ask.
We don’t put the curves on the site, because it causes confusion.
A torque curve is very specific to the actual driver, actual Voltage and resolution, and will vary greatly with different drivers, voltage and resolution.
The comment about the Chinese are not good at detent torque and the French are better, is laughable when you consider that 99% of stepper motors are made in China, and out of the 1% made elsewhere only 1% of those are made in France, and they have laminations Stamped in China :)