- RISCV processor
- Standard Logic board
- Standard Screen
- Standard Battery
- Standard Wifi & Bluetooth modem
- Probably ditch cellular and use something like LoRa
- Standard OS (Linux)
- Standard package manager
Edit: Imagine a phone that you can just swap and mix components from different manufacturers. You could buy the components yourself and assemble, like a standard PC. If one manufacturer tries to lock you in, or you don't like their component you simply replace it.
This is absolutely a non-starter. LoRa is an extremely low bandwidth protocol - in a best-case scenario (e.g. two nearby devices communicating on an uncontended frequency), it's in the realm of 50 kbit/sec. It's designed for low-rate data like remote telemetry, not real-time communications.