And what I'm saying is that there's no way to set a terminal's permissions on the host system such that it can access the internet on behalf of the user but cannot access the internet on behalf of its creators.

This is a human problem, not a software one. Your terminal is as trustworthy as its creators. It cannot be locked down to prevent telemetry and still be a useful terminal. That was my original point and it is still true.

No one should use a for-profit terminal emulator, especially one created by a VC-backed startup, full stop.