For anyone looking for an off-the-shelf solution for wireless texting, I've used the BTECH GMRS-PRO. You can send messages on the device, but it's much easier to connect it to your phone via BLE and text through the app.
However, it uses GMRS bands, not LoRA, so all the FCC restrictions apply.
However, it uses GMRS bands, not LoRA, so all the FCC restrictions apply.