The shape and form of the flat earth are both a circle.
so that sentence makes no sense.
a "circle" is not a form. forms are 3-d; shapes are 2-d. a circle is 2-d.
what you're talking about as far as the "form" of the earth isn't a "circle" -- it's more properly, a "disk" -- something with a thickness.
the Hebrew word in Isaiah 40:22 translated "circle" is a 2-d geometry word.
there is a different word that means "disk" or "wheel" -- something with a thickness, a 3-d geometry word -- that is not the one used in that passage.
so what i hope you will realize, is that your basis for this whole silly goose-chase is a fundamental misunderstanding of geometric vocabulary.
in Isaiah 40:22 the scripture is not talking about a 3-dimensional "form" -- it's not describing the "shape" of the Earth any more than the figurative verse about the angels at the "four corners" is telling us that the Earth is rectangular.
this is a 2-d word, "circle" -- it's describing a purely 2-d concept: perimeter. the breadth of all you can see in every direction if you were to look around you. as far as you could reach if you stuck out your hands and twirled. it's not describing the "form" of the Earth, dude -- if it were, it would use a 3-d geometry word, not a 2-d one, because we do not live in Flatland.
it's describing an 'encompassing distance' -- it means, the Lord sits over the "whole of the Earth"