You can't have security if you have a MITM that says "compromise your endpoint or we block you" and you concede to that. The only real solutions are either political or making the encrypted traffic look like some permitted traffic. (Or using a different network.)
You don't need to use a publicly available CA to verify client-side certificates. The server could use its own internal CA to sign CSRs from clients and send the reslting certificate back to the client via email or some other means.