Thats a lifetime of work. FOSS is difficult enough.
Our best bet is integrating into grapheneOS, calyx, linux distros and making it as easy as possible on MacOS, Windows.
cc nostr:npub1hxx76n82ags8jrduk0p3gqrfyqyaxnrlnynu9p5rt2vmwjq6ts3q4sg75y
Discussion
Possible it's closer than that.
Combination of GrapheneOS App Store + Zap Store, Amber, Pokey and perhaps some others and Google Play isn't needed at all and the whole sandbox system for Google Play Services can be deprecated. It's headache anyways.
With a hardware partner (perhaps a company like nostr:nprofile1qqswhhhf99z77pfg80s2c00z27rusxn2tzss7450n34krkwa2yadhtgpp4mhxue69uhkummn9ekx7mqpz3mhxue69uhkummnw3ezuerkv36zuer9wcq3vamnwvaz7tmpw5h8yetvv9ukzcnvv5hx7un8lpntld) phones could be distributed with it.