nowholeself said:
The plan is a gear reduction from a Neumotor 8057 to a bike chainwheel. A wormdrive is quiet, and also offers the ability to mount the motor 90 degrees off the bottom bracket axle, which helps with the design I'm tinkering with.
This may not be what you were planning , but before the current tsunami of mid drives, a whole range of Ebikes used a 90deg motor on the bottom bracket with this reducer unit.
It was fitted to Gette, Aseako, Zoco, iGo, Wolf, Ecotekk, and some other brands.
https://www.aseakoelectricbikes.com.au/product/high-torque-central-drive-system/
There should be plenty of used ones around, and even new spare drive units still available.