Respectfully, I think you missed the point of my reply.
The person asked: "Would love to hear if anyone is actually using a Linux phone and enjoying it."
...so I responded about what I enjoy about using a "Linux Phone". A "$10 raspberry pi-w" is not a Linux Phone.
The question didn't address "security and privacy", so I didn't add it. Though, since you brought it up, I will answer how the Pinephone "helps with having security and privacy".
- I have hardware (cut physical power) switches to kill the Microphone, cameras (independent for front and back), and Wifi/Bluetooth.
- I am running a full GNU/Linux distro that I have a lot more confidence in their want to protect users security/privacy.
- I can run software of my choosing on it (the Pinephone actually defaults to booting on an SD card! so it encourages you to experiement with OSes).
- There is serious effort to run the mainline Linux kernel on it, so it will not be artifically obsolete in 3-5 years (or be sutck on running some ancient swiss cheese kernel in 5 years like my old Pixel/Nexus devices).
- I don't have to install/link to some opaque binaries to even boot the system.
I'm sure I can think of more, but that's all I have for now.