Sorry to clickbait with that title… but it’s actually true. I can help you improve power use by 140x—for power off power consumption, at least.

By default, the Raspberry Pi 5 (like the Pi 4 before it) leaves the SoC powered up (just in a shutdown state) when you shut down the Pi.

Because of this, a Pi 5 will still sit there consuming 1.2-1.6W when completely shut down, even without anything plugged in except power.

Source: Reducing Raspberry Pi 5’s power consumption by 140x | Jeff Geerling