Earlier quoted context omitted.
Doesn't most consumer wifi routers do that by now by default ?
Scanning for least congested freq is very common, but it only performed right before upping of AP iface and no else. So sweeping the band with AP is very impractical.
https://meraki.cisco.com/product/wi-fi/indoor-access-points/...
This thing will scan channels, as well as perform security operations.