For an M.2 M Key connector with 1 PCIe lane, you need to connect the following PCIe signals:

These signals are exposed through the M.2 M Key connector. Make sure to connect them to the corresponding pins on your device. source

what pins on the M.2 connector route to those PCIe signals?

Based on the information found, the M.2 connector has different key types, and the M Key supports 1x, 2x, or 4x PCIe Host Interfaces. For the M.2 M Key connector, the PCIe signals are as follows:

The Raspberry Pi Compute Module 4 has a power consumption of around 3.8 W to 4.0 W when idle. Source

what about when its active

The maximum power consumption for the Raspberry Pi Compute Module 4 is around 7W, which includes the 600mA 3.3V and 1.8V outputs. Source