The shimano steps controller attaches to the handlebars using two plastic clamps which have a rubber bushing / spacer between the clamp and the handlebars.
One of those bushings was lost on the GF's ebike so I replicated it and it works very well.
Print in 95A TPU for best results. I just used the default settings in Orca slicer.
The author marked this model as their own original creation.