I suppose you should. I’ve placed the stars on the firmament dome for you, as FET posits, and am helping you understand the consequences of this model.
Yes the angular speed matters. Precisely because that is the frame that is ROTATING. The linear speed of a moving object matters, when it is moving in that rotating frame.
In fact, unless the Planar Earth is also rotating, you can’t have a Coriolis effect. That is what I’m trying to help you understand.
If it’s just the down that rotates, you won’t see any coriolis unless you are glued onto it and watching something move below you on the Earth.
Aside from how you're still trying to insist you know what I believe better than I do, it is not literally the stars reaching down that causes the coriolis effect, it's just that the force responsible for their motion doesn't vanish with altitude. There is another angular force acting at the Earth's surface, slower at the poles and faster at the equator, that acts in a set direction and as such will deflect motion in said direction. How would that have no effect, in your view?
The force responsible for their motion doesn’t vanish with altitude. What force is responsible for the stars’ motion?
If I understand you correctly, then you posit a stationary plane Earth, that contains a force which has an azimuthal angle dependence but not polar angle dependence, and also not radially dependent. So the same force that manifests as a coriolis force on the earth is responsible for the rotation of the stars. Am I getting that right?
A clever idea. Here’s the problem. The force that causes the stars to rotate must do so such that we observe neither a radial nor azimuthal dependence. Otherwise, certain strips of the night sky would rotate faster. But it all rotates together. You can see this on time lapse photography.
Hence, this motion is consistent with a centrifugal force, not a coriolis one. That is, according to your idea, we should all be flung off the Earth’s plane!