In the meantime we could look in the future how to disable this spiking even when WiFi is disabled on bootup.

This indicates that the Broadcom Wi-Fi/Bluetooth radio creates a frequency spike when it's enabled which does not imply it's transmitting anything, and if it was it would almost certainly be a randomized scan which should be possible to detect.

What we've said is that disabling cellular keeps it off during boot due to how it's initialized. We haven't looked into or talked about Broadcom Wi-Fi/Bluetooth. If people are concerned about it potentially doing a Wi-Fi scan at boot, we can look into it, but those scans don't enable tracking. If you're hiding from a eldritch horror attracted by radio waves then that could matter. We can look into that and likely stop it but it doesn't mean there's any general privacy issue caused by Wi-Fi/Bluetooth initialization right now.