Better than guessing at which WiFi channels are free is to use a WiFi utility on your smartphone, which will tell you which ones are less crowded. I say "less crowded" because there are in apartments and other locations so many WiFi signals that they tend to crowd each other.

While using OpenWRT is a valid solution, it is too technically advanced for most people with WiFi in their home. Note also that the point of my exercise was to get rid of WifI units down to a single, powerful one -- and not have a mesh of them!

ethernet-over-110ac-wiring adapters work poorly -- slow, with too many dropped connections. I've tried two different brands of them. They, in effect, extend the ethernet wiring, not the WiFi range. At the other end, you still need to add a WiFi box, so the problem still is not solved. A commercial grade WiFi indeed does transmit more power than a home-use one, just as a commercial-grade GPS is more accurate than consumer models.

Today's mice from Logitech last a long time on a battery. I recommend against the ones with rechargeable batteries: They do not run as long as chargeable ones They need to be plugged in, so you are back to have a corded mouse You have to hunt down replacement rechargeable batteries, which cost a lot more than regular batterers bought in buld.