Or.. CVT. I mean, "why stop at 10"

conic splines and rubber belts. what could possibly go wrong..

CVTs in cars have steel belts[1], or at least most do as far as I understand.

[1]: https://ricksfreeautorepairadvice.com/understanding-the-inne...

I'm showing my age:

> Many early model CVTs used a rubber belt with impregnated steel elements. However most late model CVT transmissions use a steel ring with steel elements.

We could use a planetary gear train with motor generators to make an infinite speed transmission.