> you absolutely must press the pairing button on the sensor first to wake it up before sending the new reporting configuration. Sending the payload while the device is asleep just gets ignored

This stuff is still so user unfriendly.

Why cannot the software just save the desired setting to set it when the device comes online next? I feel like many things in zigbee2mqtt are like that: I click something, it fires off some message and it often isn't clear if that worked, if it'll work later, and so on.

Because the sensors are not listening their radio transceiver (RX), only transmitting (TX), by default, to save battery.