I also got one and was pretty disappointed, so it has been left sitting on a shelf. I didn't fully understand what I would be getting. The software is unstable, in particular sometimes the app store equivalent just doesn't work. I really wanted to support the ecosystem outside of the existing duopoly but it just feels too unpolished and limited. Tried figuring out how to setup a development environment but it didn't…
> buy up some mainstream phone and sell modded versions of it with kill switches
Making the connections for the several different kill switches (cellular, wifi, microphone) on a phone whose form factor was not expressly designed for that, would probably result in a rather ugly-looking hack. Moreover, on the PinePhone at least, the cell modem is separate from the wifi chip, so you can kill one while leaving the other on, but I believe that on most phones they are part of the same SoC.