In that case hardware wise you are out of options. With the Librem 5 you get the closest. There you only have the CPU Microcode, Wifi and Bluetooth firmware, and the cellular modem & GNSS firmware.
Software wise you have quite a few options, albeit few are usable as daily drivers.
Android drops out because it requires hardware with proprietary HAL. You would have to rewrite huge parts of the OS so that it runs without them.
Postmarket OS is your best bet for a somewhat usable experience
Many open source systems run, but calls are difficult to setup and partly unreliable.
Pure OS should fit your goal best, Mobian second.
With a Droid 4 and Maemo Leste you can also get quite close but have no camera.