You are not understanding. The two polar axi with circumpolar stars and trails means either the Earth is a sphere, or the stars are a spherical shell. The dome is impossible. There is no shape of a dome that could produce those star trails. Infinite Earth plane is impossible since the star trails define only two options: 1. Spherical Earth which spins once approximately every 24 hours. or 2. The stars are a spherical shell rotating around Earth in its center approximately once every 24 hours.
If you can’t even agree on this, then make the case for how a dome would match these observations.
I believe I am understanding.
You are under the impression that lines or planes cannot intersect when it is patently clear math teaches it can.
While I cannot fundamentally comprehend the concept of infinity, it cannot be dismissed for math teaches all lines and planes are (ultimately) infinite.
Perhaps the dome is composed of permeable material allowing for intersecting the flat earth plane.
What possible portion of any possible sphere could be apparent to observers on a flat plain?
A hemisphere or dome.
It is perfectly in line with real world observations.
The way I see it, the only possible way that a celestial sphere could match real world observations in a flat earth context is if the earth was very small and the celestial sphere actually surrounded it sorta like this:
See above.