@Yveaux Thanks for the suggestions, will definitely look into this. I suspect though that something is actually going wrong with my setup, since with this power draw, I couldn't possibly reach the longevity that @m26872 got out of their sensors using the same components. Especially the fact that my draw doesn't seem to reduce at all while sleeping seems very strange to me and to me suggests that something other than the hardware specs are to blame.

I'm trying to build a battery powered temperature and humidity sensor. I used the wiring from https://forum.mysensors.org/topic/486/my-2aa-battery-sensor and started
with the sketch from https://www.mysensors.org/build/humidity (battery monitoring will be added later). Exact components are:

• https://www.aliexpress.com/item/10pcs-lot-Pro-Mini-328-Mini-3-3V-8M-ATMEGA328-3-3V-8MHz-for-arduino/1967122432.html?spm=a2g0s.9042311.0.0.M4C5Ug
• https://www.aliexpress.com/item/10PCS-NEW-NRF24L01-2-4GHz-Antenna-Wireless-Transceiver-Module/32327366606.html?spm=a2g0s.9042311.0.0.dT2xho
• https://www.aliexpress.com/item/New-Electric-Unit-1-PC-NEW-DC-0-8-3-3V-to-DC-3-3V-StepUP/32724361266.html?spm=a2g0s.9042311.0.0.dT2xho
• https://www.aliexpress.com/item/DHT22-AM2302-Humidity-temperature-and-humidity-sensor-probe-digital-output-Free-shipping-to-Malaysia/1086124515.html?spm=a2g0s.9042311.0.0.M4C5Ug

The sensor works fine and reports the measurements to the gateway, but is drawing too much power to feasibly run on battery, around 8mA consistently, i.e. whether in sleep or not. The power LED has been removed. There may have been some short-circuits from sloppy soldering initially, but I'm fairly confident they have all been resolved now. At this point I don't know what else I can do to try to diagnose this, so I would be grateful for any ideas.