Thanks for the fast answers to descartes and LoRa Tracker!
I’m at the beginning - TTN will be the next step.
Sorry, the previous diagram is only for presenting the connections to LoRa module.
I have prepared a more accurate diagram. The power supply is 3.3V.
The MCU is not NANO, but PRO MINI. In normal mode it takes about 5 mA and goes under 1 mA in sleep mode.
The transmitter works already a week, except for the current consumption of the XL1278 module.
< redacted LoRa P2P code >