Sorry, I don't know if it's meant as workaround.
M5Stack is not shy to use the term 'ultra low power' or 'very low power' for their products. And that is correct for several ICs used in M5Stack devices, like the ESP32 itself and yes, LoRaWan etc.
Unfortunately however, in my experience, the way M5Stack integrates those low power ICs into their products very often isn't ideal to create a low power device. But to be fair, they also need to ensure, that stacking various modules to the older cores (Basic, Fire, etc.) and newer cores like M5Core2 do not destroy each other. So, it could very well be that the two diodes I mentioned before are a precaution.
BTW: I myself asked this question a long time ago for M5Core2, but it never got an answer.