@alexsh1
the board on the picture is as simple has
Arduino Mini 8MHz 3.3V (no regulator or power led)
SI7021 direct I2C wiring (no regulator)
RFM95 direct SPI wiring with DIO0/DIO1/DIO2 connected see schematic on github above
Removed BOD from fuse (can be done by software) and no Watchdog use, that’s it but may be my measurement are not “so good”, but look like the same with my multimeter (1uA) and UCurrent (0.778uA) so I think I can trust the results