Though it looks like that could change eventually with a Linux phone.
Nope. There is firmware on cellular modems that is controlled by the chip vendor.
Carriers work with chip companies to make sure devices work on their network but they don’t even get the source, just early release blobs for the network engineers head of the device’s release.
This code is literally the most widely used closed source code. It is more locked down than the firmware on any other device you own. It often illegal to reverse engineer.
I’m sure one day there will be open source code for this but it’s going to come long after a Linux phone and until we can be anonymize with the tower, there is no privacy.