Some questions to JAZZCNC or any other closed loop stepper experts

[JAZZCNC]

Perhaps you are right but there is mention of "1.2 degree step angle" and "closed loop stepper vs open loop stepper" in the description. The photo of the internals also looks pretty much identical to my Leadshine. It's often hard to tell from the websites, as they are often cobbled together from all sorts of random graphics and machine translated Chinglish.

I see that JMC do both integrated stepper and integrated servo motors in the same mechanical concept, so there ARE some out there. They do a 400W, 60mm, 3.5Nm (pk), 3000rpm true AC servo for about £100 on AliExpress etc, which is starting to sound quite interesting. It's only 48V though, so would need a meaty PSU. It's possible the link earlier is to a JMC or one of its clones of course.

https://www.jmc-motor.com/product/978.html
https://www.jmc-motor.com/ntegratedservomotors.html

Ah maybe we are at cross purposes here, I was talking about the link I gave to DC servos which are just like those JMC motors, the link the OP gave was for a closed-loop stepper.
To be honest it was the JMC I was thinking about but couldn't remember where I'd seen them..