Frankenstein build (Fliteboard, Gong V2 mast, Flipsky 75200 VESC and in my case a Tritonfoils X1 monofoil)

[S_Roger]

The motor clamp @Kian made is nice and simple, but it does look like a lot of cnc cutting to produce it. You could try this other mount and maybe get the equivalent part that interfaces motor and mast cnc cut. Would be heavier for sure, but less time to make.