From a quick look, yes they would and the NetGuard FAQ on GitHub explicitly acknowledges that: https://github.com/M66B/NetGuard/blob/master/FAQ.md#user-con...

That doesn't mean this is a worthless thing to run. Unless you are being specifically targeted, security measures that simply put you outside the main herd can still be effective.

Both the hardware vendor and the vendor of the mobile phone's "black box" talking to your telecom could, of course. Potentially some chips inside could do nasty things, even if you'd install LineageOS for example.