Another thought by me is that an expert/advanced PT- or even a expert chiro should be able to do some postional , traction , compression tests to verify if the sx are from the c spine vs the TOS.

At least that's what 2 PTs and the chiro did - none of the MDs did any "hands on" testing like that.

Have you had any "hands on" type of thorough evaluation?

a good one will take approx 1 hour or so.
Positional testing is very helpful indicator {but not a conclusive test, just good to have it verified} - not just