The company that made the Nexdock is planning to make a phone. It will be Android but it can bring up a full Linux desktop that can access the Android storage. I am considering getting it and only using Android for calls, texts, and a couple apps while I install phosh UI in the distro and focus on using that.

https://nexphone.com/

There is a self-hosted app you can run to pretend to be a Google bot and bypass paywalls and forced login. https://github.com/wasi-master/13ft

Now you have to move on to obscure open source hardware. Linux phone and/or a RISC-V computer

For dual booting with windows, I find this guide from System76 to be pretty good. https://support.system76.com/articles/windows/