Spoke too soon. Went back to being rubbish.Interesting. I've reported the same issue, in my case with Ubiquiti (UniFi and AmpliFi) WiFi routers, but I never get any suggestions about channel allocation from anyone, including Chord support. I know Chord don't have access to that gear in the UK, but at the very least they could tell us their recommendations on channel allocation.
I would link that to Sunday being far less congested vs Monday when people work from home and use their internet more.
It seems like my only alternative is to use the Hugo2Go via ethernet, which is not something I will likely do.