Xfinity Gateway 2.4GHz 40MHz channel width by default, is bad.

It is exceedingly rare for the 2.4GHz and Bluetooth radios to interfere with each other.  A properly configured bluetooth radio will not interfere with wifi, due to the use of frequency hopping spread spectrum (FHSS).  I am retired now, but spent years in IT, and I can say with some experience that bluetooth issues are rarely caused by signal overlap. Here is an article that discusses the basics:

https://community.estimote.com/hc/en-us/articles/200794267-Will-wireless-interference-and-Wi-Fi-impact-beacons-

I would think the only time it would be an issue is when a computer connecting via wifi is located very, very close to the router.  In that scenario, if interference does occur, the easiest and best fix is to connect via ethernet. 

In your experience, with 2/3 the 2.4Ghz spectrum being consumed using a 40MHz channel, say someone begins a torrent, console game download, or Steam download; How would that affect other 2.4GHz wireless mediums? All I am saying is it is very bad practice to enable 40MHz on the 2.4GHz by default, and now the WiFi 6 and 6E Xfinity Gateway’s don’t even give you the option to change channel number or the channel width. Thus, the only fix would essentially be a firmware update. Wouldn’t you agree?

f you want such fine grained control over your network, then you will have to ditch the hardware provided by comcast and buy your own. 

That is what I do, so it wasn’t until I installed their hardware for a family member, that I noticed this “bad neighbor” configuration which I was able to modify on that particular Gateway(XB3), but subsequent models have their WiFi channel and channel width settings locked down. This creates big problems especially with the default shared SSID between both bands configuration. Which you can’t control what band you’re connecting to in case of a episode of WiFi service disruption/degradation which will be very common with such a channel width configuration on the 2.4GHz band.

As I stated earlier, if you want to have any degree of real control over *YOUR* home network, you will have to return the hardware, buy your own compatible hardware, set the SSIDs for each band the same, and let the router do it's job.  It will detect bandwidth/latency issues and reassign clients as necessary.  Just a few years ago, when most clients were 2.4GHz and the extra channels were not allocated, there were times when a band could have issues, but the technology in both routers and clients have come a long way since then.