There are inventor programs that'll literally ship you to Shenzhen to build connections to manufacturing sites and even provide you with a liaison, etc. I only know this because I was once in a program that did exactly this.

Rewinding drone motors for high torque and lower speed seems to be a popular thing. Here's the commercial process of machine winding motors like that.[1] That's a medium-volume machine, loaded and unloaded by hand, and adjustable for different wire and motor geometry. Here's a hobbyist version of a similar winder.[2] And another automatic hobbyist winder. Those wind under uniform tension, and with wire positioning, so you get a smooth, tight winding. This matters if you're going to use the motor much. Doesn't matter as much for short-lived toys.

There should soon be enough convergence that low cost, high torque, low speed models are off the shelf items. It's a great time to be building robots. Used to be all uphill on the parts side.

[1] https://www.youtube.com/watch?v=cMk2qFFcSho

[2] https://www.youtube.com/watch?v=486nUU2FjGU

[3] https://www.youtube.com/watch?v=e-tAsM0K7Sg

Reminder that this was a student project.