It seems from what you are describing your software is more like (replicad)[https://github.com/sgenoud/replicad]
The user can create planes with plane() command e.g plane("xy") or plane("xy", { offset: 10 }); but I have added some shortcuts for common planes (https://fluidcad.io/docs/guides/sketching/introduction#sketc...)
you can also sketch on faces sketch(extrusion.endFace(), ...) which will extract the plane from face and put the starting point on the center for convinience.
Had a bit of a rethink after this, settling on name spacing more like this at the moment. Quite enjoying the cycle of build/try/improve.
const in1 = draw.rectangle(size1, size1).fillet(2)
const in2 = draw.origin([0,0,height1]).rectangle(size2, size2).fillet(2)
const result = make.loft([in1, in2])
Inspired by yes, it was one of the ones I tried. I like your approach to selection eg endFace, intuitive selection is definitely one of the trickier parts of a code based approach.